[clang-tools-extra] [clang-tidy] add fixhint for misc-use-internal-linkage (PR #96203)

[Congcong Cai via cfe-commits]

================
@@ -25,3 +25,16 @@ Example:
   }
   // already declared as extern
   extern int v2;
+
+Options
+-------
+
+.. option:: FixMode
+
+  Selects the fix mode when fixing automatically.
----------------
HerrCai0907 wrote:

```suggestion
  Selects what kind of a fix the check should provide.
```

https://github.com/llvm/llvm-project/pull/96203