Update clippy_lints/src/methods/mod.rs

Grammar fix.

Author: xiongmao86

clippy_lints/src/methods/mod.rs

@@ -1107,7 +1107,7 @@ declare_clippy_lint! {
     ///
     /// **Why is this bad?** When people testing a file type with `FileType::is_file`
     /// they are testing whether a path is something they can get bytes from. But
-    /// `is_file` doesn't cover special file types in unix-like systems. and not covering
+    /// `is_file` doesn't cover special file types in unix-like systems, and doesn't cover
     /// symlink in windows. Using `!FileType::is_dir()` is a better way to that intention.
     ///
     /// **Example:**