宏的缩进功能

(Newest and best option in my opinion—available as ofClang-Format version 9) Indent before the hash (#)

IndentPPDirectives: BeforeHash

https://stackoverflow.com/questions/24476165/indenting-preprocessor-directives-with-clang-format/66004745#66004745

https://releases.llvm.org/9.0.0/tools/clang/docs/ClangFormatStyleOptions.html