clang-format: [JS] fix `of` detection.
Summary:
`of` is only a keyword when after an identifier, but not when after
an actual keyword.
Before:
return of (a, b, c);
After:
return of(a, b, c);
Reviewers: djasper
Subscribers: cfe-commits, klimek
Differential Revision: https://reviews.llvm.org/D43440
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@325489 91177308-0d34-0410-b5e6-96231b3b80d8