[clang-tools-extra] [clang-tidy] add new check: modernize-use-scoped-lock (PR #126434)

[Piotr Zegar via cfe-commits]

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+.. title:: clang-tidy - modernize-use-scoped-lock
+
+modernize-use-scoped-lock
+=========================
+
+Finds uses of ``std::lock_guard`` and suggests replacing them with C++17's more
+flexible and safer alternative ``std::scoped_lock``. The check will
+automatically transform only single declarations of ``std::lock_guard`` and
+emit warnings for multiple declarations of ``std::lock_guard`` that can be
+replaced with a single declaration of ``std::scoped_lock``.
+
+Examples
+--------
+
+Single ``std::lock_guard`` declaration:
+
+.. code-block:: c++
+
+  std::mutex M;
+  std::lock_guard<std::mutex> L(M);
+
+
+Transforms to:
+
+.. code-block:: c++
+
+  std::mutex m;
----------------
PiotrZSL wrote:

```suggestion
  std::mutex M;
```

https://github.com/llvm/llvm-project/pull/126434