correct "Affected lints" for allow-one-hash-in-raw-strings (#14186)

The `needless_raw_string_hashes` lint was implemented in #10884.
However, the name originally considered might have been
`unnecessary_raw_string_hashes`, so this part refers to a non-existent
lint.

r? flip1995

changelog: none

Author: flip1995

Diff for: book/src/lint_configuration.md

@@ -108,7 +108,7 @@ Whether to allow `r#""#` when `r""` can be used
 
 ---
 **Affected lints:**
-* [`unnecessary_raw_string_hashes`](https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_raw_string_hashes)
+* [`needless_raw_string_hashes`](https://rust-lang.github.io/rust-clippy/master/index.html#needless_raw_string_hashes)
 
 
 ## `allow-panic-in-tests`

Diff for: clippy_config/src/conf.rs

@@ -298,7 +298,7 @@ define_Conf! {
     #[lints(uninlined_format_args)]
     allow_mixed_uninlined_format_args: bool = true,
     /// Whether to allow `r#""#` when `r""` can be used
-    #[lints(unnecessary_raw_string_hashes)]
+    #[lints(needless_raw_string_hashes)]
     allow_one_hash_in_raw_strings: bool = false,
     /// Whether `panic` should be allowed in test functions or `#[cfg(test)]`
     #[lints(panic)]