[clang-tools-extra] [clang-tidy] new check readability-mark-static (PR #90830)

[Danny Mösch via cfe-commits]

================
@@ -151,6 +151,11 @@ New checks
   Enforces consistent style for enumerators' initialization, covering three
   styles: none, first only, or all initialized explicitly.
 
+- New :doc:`readability-unnecessary-external-linkage
+  <clang-tidy/checks/readability/unnecessary-external-linkage>` check.
+
+  Detects variable and function can be marked as static.
----------------
SimplyDanny wrote:

```suggestion
  Detects variables and functions that can be marked as static
  or moved into an anonymous namespace to enforce internal linkage.
```

https://github.com/llvm/llvm-project/pull/90830