fix key name of MUTABLE_KEY_TYPE

Author: koka831

book/src/lint_configuration.md

@@ -517,7 +517,7 @@ for the generic parameters for determining interior mutability
 
 **Default Value:** `["bytes::Bytes"]` (`Vec<String>`)
 
-* [mutable_key](https://rust-lang.github.io/rust-clippy/master/index.html#mutable_key)
+* [mutable_key_type](https://rust-lang.github.io/rust-clippy/master/index.html#mutable_key_type)
 
 
 ### allow-mixed-uninlined-format-args

clippy_lints/src/utils/conf.rs

@@ -437,7 +437,7 @@ define_Conf! {
     ///
     /// The maximum size of the `Err`-variant in a `Result` returned from a function
     (large_error_threshold: u64 = 128),
-    /// Lint: MUTABLE_KEY.
+    /// Lint: MUTABLE_KEY_TYPE.
     ///
     /// A list of paths to types that should be treated like `Arc`, i.e. ignored but
     /// for the generic parameters for determining interior mutability