[Docs][clang-tools-extra] Convert maintainers list to .rst format (#165171)

[Clang maintainers
list](https://github.com/llvm/llvm-project/blob/main/clang/Maintainers.rst)
is already in `.rst` format, which gives nice visuals.
I think we should convert clang-tools-extra maintainers too to `.rst`.

clang-tools-extra/Maintainers.rst

@@ -2,9 +2,13 @@
 Clang Tools Extra Maintainers
 =============================
 
-This file is a list of the maintainers
-(https://llvm.org/docs/DeveloperPolicy.html#maintainers) for clang-tools-extra.
+This file is a list of the 
+`maintainers <https://llvm.org/docs/DeveloperPolicy.html#maintainers>`_
+for `Extra Clang Tools <https://clang.llvm.org/extra/index.html>`_ project.
 
+.. contents::
+   :depth: 2
+   :local:
 
 Active Maintainers
 ==================

clang-tools-extra/docs/Maintainers.rst

@@ -0,0 +1 @@
+.. include:: ../Maintainers.rst

clang-tools-extra/docs/index.rst

@@ -22,6 +22,7 @@ Contents
    pp-trace
    clangd <https://clangd.llvm.org/>
    clang-doc
+   Maintainers
 
 
 Doxygen Documentation