Update clippy_lints/src/methods/mod.rs

Fix grammar problem.

Co-Authored-By: Philipp Krones <[email protected]>

Author: xiongmao86

clippy_lints/src/methods/mod.rs

@@ -1121,7 +1121,7 @@ declare_clippy_lint! {
     /// }
     /// ```
     ///
-    /// should be writing as:
+    /// should be written as:
     ///
     /// ```rust,ignore
     /// let metadata = std::fs::metadata("foo.txt")?;