[clang-doc] sys::fs::F_None -> OF_None. NFC

F_None, F_Text and F_Append are kept for compatibility.

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@371394 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed