[Windows] Add git-clang-format wrapper bat file (llvm#69228)

This allows git-clang-format to be used on a Windows terminal without
manually needing to find the path and invoke the python interpreter. We
have a similar script for `scan-build`.

Fixes llvm#69643

Author: llvm-beanz

clang/tools/clang-format/CMakeLists.txt

@@ -38,3 +38,9 @@ install(FILES clang-format.py
 install(PROGRAMS git-clang-format
   DESTINATION "${CMAKE_INSTALL_BINDIR}"
   COMPONENT clang-format)
+
+if (WIN32 AND NOT CYGWIN)
+  install(PROGRAMS git-clang-format.bat
+    DESTINATION "${CMAKE_INSTALL_BINDIR}"
+    COMPONENT clang-format)
+endif()

clang/tools/clang-format/git-clang-format.bat

@@ -0,0 +1 @@
+py -3 git-clang-format %*