Apply nightly rustfmt rules.

Applied via `make rustfmt`, which enables these nightly-only rules:
```
group_imports = "StdExternalCrate"
imports_granularity = "Crate"
```

Keep git-config in its original form for now

cargo-smart-release/src/command/release/cargo.rs

@@ -1,7 +1,9 @@
-use super::{utils::will, Options};
+use std::process::Command;
+
 use anyhow::bail;
 use cargo_metadata::Package;
-use std::process::Command;
+
+use super::{utils::will, Options};
 
 pub(in crate::command::release_impl) fn publish_crate(
     publishee: &Package,

cargo-smart-release/src/command/release/git.rs

@@ -1,6 +1,5 @@
-use super::{Context, Options};
-use crate::command::release_impl::tag_name_for;
-use crate::command::release_impl::utils::will;
+use std::{convert::TryInto, process::Command};
+
 use anyhow::{anyhow, bail};
 use bstr::ByteSlice;
 use cargo_metadata::{
@@ -20,7 +19,9 @@ use git_repository::{
     },
     Repository,
 };
-use std::{convert::TryInto, process::Command};
+
+use super::{Context, Options};
+use crate::command::release_impl::{tag_name_for, utils::will};
 
 pub(in crate::command::release_impl) fn has_changed_since_last_release(
     package: &Package,

cargo-smart-release/src/command/release/manifest.rs

@@ -1,13 +1,15 @@
+use std::{collections::BTreeMap, str::FromStr};
+
+use anyhow::bail;
+use cargo_metadata::{Metadata, Package};
+use git_repository::hash::ObjectId;
+use semver::{Op, Version, VersionReq};
+
 use super::{
     cargo, git,
     utils::{names_and_versions, package_by_id, package_eq_dependency},
     Context, Options,
 };
-use anyhow::bail;
-use cargo_metadata::{Metadata, Package};
-use git_repository::hash::ObjectId;
-use semver::{Op, Version, VersionReq};
-use std::{collections::BTreeMap, str::FromStr};
 
 pub(in crate::command::release_impl) fn edit_version_and_fixup_dependent_crates(
     meta: &Metadata,

cargo-smart-release/src/command/release/mod.rs

@@ -1,8 +1,10 @@
-use crate::command::release::Options;
+use std::collections::BTreeSet;
+
 use anyhow::bail;
 use cargo_metadata::{camino::Utf8PathBuf, Dependency, DependencyKind, Metadata, Package, Version};
 use git_repository::{refs::packed, Repository};
-use std::collections::BTreeSet;
+
+use crate::command::release::Options;
 
 mod utils;
 use crates_index::Index;

experiments/diffing/src/main.rs

@@ -1,3 +1,5 @@
+use std::time::Instant;
+
 use anyhow::anyhow;
 use diff::tree::visit::{Action, Change};
 use git_repository::{
@@ -10,7 +12,6 @@ use git_repository::{
     refs::file::loose::reference::peel,
 };
 use rayon::prelude::*;
-use std::time::Instant;
 
 const GITOXIDE_CACHED_OBJECT_DATA_PER_THREAD_IN_BYTES: usize = 60_000_000;
 

experiments/hash-owned-borrowed/benches/usage.rs

@@ -1,6 +1,7 @@
-use criterion::*;
 use std::borrow::Borrow;
 
+use criterion::*;
+
 fn use_owned_by_ref(id: &hash::Owned) {
     black_box(id);
 }

experiments/object-access/src/main.rs

@@ -1,6 +1,7 @@
+use std::{path::Path, time::Instant};
+
 use anyhow::anyhow;
 use git_repository::{hash::ObjectId, odb, prelude::*, Repository};
-use std::{path::Path, time::Instant};
 
 const GITOXIDE_STATIC_CACHE_SIZE: usize = 64;
 const GITOXIDE_CACHED_OBJECT_DATA_PER_THREAD_IN_BYTES: usize = 60_000_000;

experiments/traversal/src/main.rs

@@ -1,3 +1,8 @@
+use std::{
+    collections::HashSet,
+    time::{Duration, Instant},
+};
+
 use anyhow::anyhow;
 use dashmap::DashSet;
 use git_repository::{
@@ -8,10 +13,6 @@ use git_repository::{
     refs::file::loose::reference::peel,
     traverse::{tree, tree::visit::Action},
 };
-use std::{
-    collections::HashSet,
-    time::{Duration, Instant},
-};
 
 const GITOXIDE_STATIC_CACHE_SIZE: usize = 64;
 const GITOXIDE_CACHED_OBJECT_DATA_PER_THREAD_IN_BYTES: usize = 60_000_000;

git-actor/src/immutable/mod.rs

@@ -1,7 +1,8 @@
 //!
-use crate::Time;
 use bstr::BStr;
 
+use crate::Time;
+
 /// A signature is created by an actor at a certain time.
 ///
 /// Note that this is not a cryptographical signature.

git-actor/src/immutable/signature.rs

@@ -1,8 +1,6 @@
 mod decode {
-    use btoi::btoi;
-
-    use crate::{immutable::Signature, Sign, Time};
     use bstr::ByteSlice;
+    use btoi::btoi;
     use nom::{
         branch::alt,
         bytes::complete::{tag, take, take_until, take_while_m_n},
@@ -12,6 +10,8 @@ mod decode {
         IResult,
     };
 
+    use crate::{immutable::Signature, Sign, Time};
+
     const SPACE: &[u8] = b" ";
 
     /// Parse a signature from the bytes input `i` using `nom`.
@@ -65,11 +65,15 @@ mod decode {
     #[cfg(test)]
     mod tests {
         mod parse_signature {
-            use crate::{immutable::signature, immutable::Signature, Sign, Time};
             use bstr::ByteSlice;
             use git_testtools::to_bstr_err;
             use nom::IResult;
 
+            use crate::{
+                immutable::{signature, Signature},
+                Sign, Time,
+            };
+
             fn decode(i: &[u8]) -> IResult<&[u8], Signature<'_>, nom::error::VerboseError<&[u8]>> {
                 signature::decode(i)
             }

git-actor/src/signature.rs

@@ -14,10 +14,12 @@ mod convert {
 }
 
 mod write {
-    use crate::{Signature, SPACE};
+    use std::io;
+
     use bstr::{BStr, ByteSlice};
     use quick_error::quick_error;
-    use std::io;
+
+    use crate::{Signature, SPACE};
 
     quick_error! {
         /// The Error produced by [`Signature::write_to()`].

git-actor/src/types.rs

@@ -1,6 +1,7 @@
-use crate::{Sign, Signature, Time, SPACE};
 use std::io;
 
+use crate::{Sign, Signature, Time, SPACE};
+
 impl Signature {
     /// An empty signature, similar to 'null'.
     pub fn empty() -> Self {

git-commitgraph/src/file/access.rs

@@ -1,11 +1,13 @@
-use crate::file::{self, commit::Commit, File, COMMIT_DATA_ENTRY_SIZE};
-use git_hash::SIZE_OF_SHA1_DIGEST as SHA1_SIZE;
 use std::{
     convert::TryInto,
     fmt::{Debug, Formatter},
     path::Path,
 };
 
+use git_hash::SIZE_OF_SHA1_DIGEST as SHA1_SIZE;
+
+use crate::file::{self, commit::Commit, File, COMMIT_DATA_ENTRY_SIZE};
+
 /// Access
 impl File {
     /// The number of base graphs that this file depends on.

git-commitgraph/src/file/commit.rs

@@ -1,16 +1,18 @@
 //! Low-level operations on individual commits.
-use crate::{
-    file::{self, File},
-    graph,
-};
-use byteorder::{BigEndian, ByteOrder};
-use git_hash::SIZE_OF_SHA1_DIGEST as SHA1_SIZE;
 use std::{
     convert::TryInto,
     fmt::{Debug, Formatter},
     slice::Chunks,
 };
 
+use byteorder::{BigEndian, ByteOrder};
+use git_hash::SIZE_OF_SHA1_DIGEST as SHA1_SIZE;
+
+use crate::{
+    file::{self, File},
+    graph,
+};
+
 /// The error used in the [`file::commit`][self] module.
 #[derive(thiserror::Error, Debug)]
 #[allow(missing_docs)]

git-commitgraph/src/file/init.rs

@@ -1,14 +1,16 @@
-use crate::file::{File, COMMIT_DATA_ENTRY_SIZE, FAN_LEN, SIGNATURE};
-use bstr::ByteSlice;
-use byteorder::{BigEndian, ByteOrder};
-use filebuffer::FileBuffer;
-use git_hash::SIZE_OF_SHA1_DIGEST as SHA1_SIZE;
 use std::{
     convert::{TryFrom, TryInto},
     ops::Range,
     path::Path,
 };
 
+use bstr::ByteSlice;
+use byteorder::{BigEndian, ByteOrder};
+use filebuffer::FileBuffer;
+use git_hash::SIZE_OF_SHA1_DIGEST as SHA1_SIZE;
+
+use crate::file::{File, COMMIT_DATA_ENTRY_SIZE, FAN_LEN, SIGNATURE};
+
 type ChunkId = [u8; 4];
 
 /// The error used in [`File::at()`].

git-commitgraph/src/file/mod.rs

@@ -8,16 +8,16 @@ pub use commit::Commit;
 mod init;
 pub mod verify;
 
-pub use init::Error;
-
-use filebuffer::FileBuffer;
-use git_hash::SIZE_OF_SHA1_DIGEST as SHA1_SIZE;
 use std::{
     fmt::{Display, Formatter},
     ops::Range,
     path::PathBuf,
 };
 
+use filebuffer::FileBuffer;
+use git_hash::SIZE_OF_SHA1_DIGEST as SHA1_SIZE;
+pub use init::Error;
+
 const COMMIT_DATA_ENTRY_SIZE: usize = SHA1_SIZE + 16;
 const FAN_LEN: usize = 256;
 const SIGNATURE: &[u8] = b"CGPH";

git-commitgraph/src/file/verify.rs

@@ -1,16 +1,18 @@
 //! Auxiliary types used in commit graph file verification methods.
-use crate::{
-    file::{self, File},
-    GENERATION_NUMBER_INFINITY, GENERATION_NUMBER_MAX,
-};
-use bstr::ByteSlice;
-use git_hash::SIZE_OF_SHA1_DIGEST as SHA1_SIZE;
 use std::{
     cmp::{max, min},
     collections::HashMap,
     path::Path,
 };
 
+use bstr::ByteSlice;
+use git_hash::SIZE_OF_SHA1_DIGEST as SHA1_SIZE;
+
+use crate::{
+    file::{self, File},
+    GENERATION_NUMBER_INFINITY, GENERATION_NUMBER_MAX,
+};
+
 /// The error used in [`File::traverse()`].
 #[derive(thiserror::Error, Debug)]
 #[allow(missing_docs)]

git-commitgraph/src/graph/init.rs

@@ -1,13 +1,14 @@
-use crate::{
-    file::{self, File},
-    Graph, MAX_COMMITS,
-};
 use std::{
     convert::TryFrom,
     io::{BufRead, BufReader},
     path::{Path, PathBuf},
 };
 
+use crate::{
+    file::{self, File},
+    Graph, MAX_COMMITS,
+};
+
 /// The error used in the [`graph`][crate::graph] module.
 #[derive(thiserror::Error, Debug)]
 #[allow(missing_docs)]

git-commitgraph/src/graph/mod.rs

@@ -3,9 +3,10 @@ mod access;
 mod init;
 pub mod verify;
 
-use crate::file::File;
 use std::fmt;
 
+use crate::file::File;
+
 /// A complete commit graph.
 ///
 /// The data in the commit graph may come from a monolithic `objects/info/commit-graph` file, or it

git-commitgraph/src/graph/verify.rs

@@ -1,15 +1,16 @@
 //! Auxiliary types used by graph verification methods.
-use crate::{
-    file::{self, commit},
-    graph, Graph, GENERATION_NUMBER_MAX,
-};
 use std::{
     cmp::{max, min},
     collections::BTreeMap,
     convert::TryInto,
     path::PathBuf,
 };
 
+use crate::{
+    file::{self, commit},
+    graph, Graph, GENERATION_NUMBER_MAX,
+};
+
 /// The error used in [`verify_integrity()`][Graph::verify_integrity].
 #[derive(thiserror::Error, Debug)]
 #[allow(missing_docs)]

git-commitgraph/tests/access/mod.rs

@@ -1,6 +1,7 @@
-use crate::{check_common, inspect_refs, make_readonly_repo};
 use git_commitgraph::Graph;
 
+use crate::{check_common, inspect_refs, make_readonly_repo};
+
 #[test]
 fn single_parent() -> crate::Result {
     let repo_dir = make_readonly_repo("single_parent.sh");

git-commitgraph/tests/commitgraph.rs

@@ -1,4 +1,3 @@
-use git_commitgraph::{graph::Position as GraphPosition, Graph};
 use std::{
     collections::{HashMap, HashSet},
     convert::{TryFrom, TryInto},
@@ -8,6 +7,8 @@ use std::{
     process::Command,
 };
 
+use git_commitgraph::{graph::Position as GraphPosition, Graph};
+
 type Result = std::result::Result<(), Box<dyn std::error::Error>>;
 
 mod access;

git-diff/src/tree/changes.rs

@@ -1,11 +1,13 @@
+use std::{borrow::BorrowMut, collections::VecDeque};
+
+use git_hash::{oid, ObjectId};
+use git_object::immutable;
+use quick_error::quick_error;
+
 use crate::{
     tree,
     tree::{visit::Change, TreeInfoPair},
 };
-use git_hash::{oid, ObjectId};
-use git_object::immutable;
-use quick_error::quick_error;
-use std::{borrow::BorrowMut, collections::VecDeque};
 
 quick_error! {
     /// The error returned by [tree::Changes::needed_to_obtain()].

git-diff/src/tree/mod.rs

@@ -1,6 +1,7 @@
+use std::collections::VecDeque;
+
 use git_hash::ObjectId;
 use git_object::immutable;
-use std::collections::VecDeque;
 
 /// The state required to visit [Changes] to be instantiated with `State::default()`.
 #[derive(Default, Clone)]