Support inverted/closing comment markers

We should support comments like this:
```
/*==-- clang-c/BuildSystem.h - Utilities for use by build systems -*- C -*-===*\
|* SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception *|
```

The finishing `*|` should not be treated as a part of the tag.

See [reuse-tool#343](https://github.com/fsfe/reuse-tool/issues/343) for details.

See the code near this line: https://github.com/ForNeVeR/dotnet-reuse/blob/be3dd1818b0ea88685dae07cd847eab31fe6da46/FVNever.Reuse/ReuseFileEntry.cs#L82

Also, look for the number of this issue in the project code base.