[clang-format] extra space added within comments that use double asterisks to close

I'm seeing strange comment formatting behavior with clang-format 21. I've confirmed the problem exists at HEAD (LLVM 23.0.0) as well. Minimal reproducer:

```
# dot-clang-format
ColumnLimit: 80
ReflowComments: true
PenaltyExcessCharacter: 10
```

```
# test.cc
/**
* This test verifies the special code path. It currently exists for code coverage.
**/
void test() {}
```

Note how an extra space is added between "code" and "coverage":

```
$ clang-format --style=file:dot-clang-format test.cc
/**
* This test verifies the special code path. It currently exists for code coverage.
**/
void test() {}
```

This _only_ happens when the close of the comment block uses `**/` (double asterisk). If the block closes with `*/` this behavior does not occur.

Bisection reveals this was introduced with f771d08.