Add test of let dot dot

Currently fails:

    ---- test_let_dot_dot stdout ----
    thread 'test_let_dot_dot' panicked at 'called `Result::unwrap()` on an `Err` value: Error("expected one of: literal, identifier, `::`, `<`, `self`, `Self`, `super`, `crate`, `const`")', tests/test_stmt.rs:85:5
    note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

tests/test_stmt.rs

@@ -4,6 +4,7 @@
 mod macros;
 
 use proc_macro2::{Delimiter, Group, Ident, Span, TokenStream, TokenTree};
+use quote::quote;
 use std::iter::FromIterator;
 use syn::Stmt;
 
@@ -74,3 +75,19 @@ fn test_none_group() {
     })
     "###);
 }
+
+#[test]
+fn test_let_dot_dot() {
+    let tokens = quote! {
+        let .. = 10;
+    };
+
+    snapshot!(tokens as Stmt, @r###"
+    Local(Local {
+        pat: Pat::Rest,
+        init: Some(Expr::Lit {
+            lit: 10,
+        }),
+    })
+    "###);
+}