Auto merge of #4201 - mgr-inz-rafal:typos_in_docs, r=matthiaskrgr

Typos and minor grammar corrections

Just some minor grammar issues and typos in documentation.

clippy_lints/src/attrs.rs

@@ -134,7 +134,7 @@ declare_clippy_lint! {
 
 declare_clippy_lint! {
     /// **What it does:** Checks for `allow`/`warn`/`deny`/`forbid` attributes with scoped clippy
-    /// lints and if those lints exist in clippy. If there is a uppercase letter in the lint name
+    /// lints and if those lints exist in clippy. If there is an uppercase letter in the lint name
     /// (not the tool name) and a lowercase version of this lint exists, it will suggest to lowercase
     /// the lint name.
     ///

clippy_lints/src/double_comparison.rs

@@ -9,7 +9,7 @@ use syntax::source_map::Span;
 use crate::utils::{snippet_with_applicability, span_lint_and_sugg, SpanlessEq};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for double comparions that could be simplified to a single expression.
+    /// **What it does:** Checks for double comparisons that could be simplified to a single expression.
     ///
     ///
     /// **Why is this bad?** Readability.

clippy_lints/src/functions.rs

@@ -56,7 +56,7 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for public functions that dereferences raw pointer
+    /// **What it does:** Checks for public functions that dereference raw pointer
     /// arguments but are not marked unsafe.
     ///
     /// **Why is this bad?** The function should probably be marked `unsafe`, since

clippy_lints/src/indexing_slicing.rs

@@ -37,7 +37,7 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for usage of indexing or slicing. Arrays are special cased, this lint
+    /// **What it does:** Checks for usage of indexing or slicing. Arrays are special cases, this lint
     /// does report on arrays if we can tell that slicing operations are in bounds and does not
     /// lint on constant `usize` indexing on arrays because that is handled by rustc's `const_err` lint.
     ///

clippy_lints/src/needless_bool.rs

@@ -19,7 +19,7 @@ declare_clippy_lint! {
     /// **Why is this bad?** Redundant code.
     ///
     /// **Known problems:** Maybe false positives: Sometimes, the two branches are
-    /// painstakingly documented (which we of course do not detect), so they *may*
+    /// painstakingly documented (which we, of course, do not detect), so they *may*
     /// have some value. Even then, the documentation can be rewritten to match the
     /// shorter code.
     ///

clippy_lints/src/types.rs

@@ -1495,7 +1495,7 @@ declare_clippy_lint! {
     /// checked.
     ///
     /// **Why is this bad?** An expression like `min <= x` may misleadingly imply
-    /// that is is possible for `x` to be less than the minimum. Expressions like
+    /// that it is possible for `x` to be less than the minimum. Expressions like
     /// `max < x` are probably mistakes.
     ///
     /// **Known problems:** For `usize` the size of the current compile target will