make update_docu_links independet on the location it is called from

[5ila5]

This can wait until #5577 is through

[bbr111]

Thanks for making the script independent of the current working directory. The general approach of resolving paths relative to file looks good.

There is one cross-platform regression compared with the previous implementation:

@Property
def relative_file_path_name(self):
return "/" + str(self._file.relative_to(PROJECT_ROOT))

The previous implementation constructed documentation links explicitly with /, for example:

filename = f"/doc/source/{file}.md"

With the new implementation, str(Path(...)) uses the platform-specific path separator. On Windows this can generate links such as:

/doc\source\example.md

Since this value is used for Markdown links and GitHub documentation URLs, it should always use POSIX separators:

@Property
def relative_file_path_name(self) -> str:
return "/" + self._file.relative_to(PROJECT_ROOT).as_posix()

Apart from this cross-platform issue, the path refactoring looks good.

[bbr111]

but maybe we should wait until the BaseSource PR is merged.