Keep trailing annotations close to their argument.

Before:
bool aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa GUARDED_BY(
    aaaaaaaaaaaa);

After:
bool aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
    GUARDED_BY(aaaaaaaaaaaa);

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@186077 91177308-0d34-0410-b5e6-96231b3b80d8