[clang] [docs][clang-format] Rename clang-format docs *.rst -> *.md, update refs (PR #211397)

[via cfe-commits]

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@@ -83,7 +83,7 @@ add_custom_target(clang-format-style DEPENDS ${format_style_depend})
 
 set(format_help_depend ${CMAKE_CURRENT_BINARY_DIR}/format_help_depend)
 set(dump_help dump_format_help.py)
-set(clang_format_rst ${CLANG_SOURCE_DIR}/docs/ClangFormat.rst)
+set(clang_format_rst ${CLANG_SOURCE_DIR}/docs/ClangFormat.md)
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owenca wrote:

Ditto.

https://github.com/llvm/llvm-project/pull/211397