[clang-format] Avoid adding space after the name of a function-like macro when...

[clang-format] Avoid adding space after the name of a function-like macro when the name is a keyword.

Fixes https://github.com/llvm/llvm-project/issues/31086.

Before the code:
```
#define if(x)
```

was erroneously formatted to:
```
#define if (x)
```

Reviewed By: HazardyKnusperkeks, owenpan

Differential Revision: https://reviews.llvm.org/D118844