clang-format: If in doubt, assume '+' is a binary operator.

Before:
  #define LENGTH(x, y) (x) - (y)+1

After:
  #define LENGTH(x, y) (x) - (y) + 1

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@219119 91177308-0d34-0410-b5e6-96231b3b80d8