This reverts commit 01f09888208341876d1480bd22dc8f4107c100f1.

The whitespace handling and trailer selection isn't very trivial or good
documented. It therefore seemed easier and less error prone to just call
git to parse the message for the trailers section and remove superfluos
whitespaces.

With the command `git interpret-trailers` git provides a way to interact
with trailer lines in the commit messages that look similar to RFC 822
e-mail headers (see: https://git-scm.com/docs/git-interpret-trailers).
The new property returns those parsed trailer lines from the message as
dictionary.

Use NUL character instead of semicolon to extract meta and path. Avoid errors in during git diff when dealing with filenames containing semicolons

With each patch level it may bring up new issues that cause CI failure
for without being related to the actual change.

This isn't needed as git will replace this file atomicially,
hence we always see a fully written file when reading.

Only when writing we need to obtain a lock.

The original change requiring py3.10 TypeGuard (and matching
typing_extensions) has been reverted, so revert the requirement
on typing_extensions as well.