Using # or ; in config values #2214

Before #2211 we used json.dumps to write branch names to Git configuration to deal with special chars. The pull request seems to address part of the issues and breaks our approach of quoting strings (what I believe is correct), but it still doesn't handle some special characters as it doesn't quote # or ;. Both of these are treated as comments when reading the configuration with Git, so the set value is truncated there.

Reproducer: gitpython-config-comment-reproducer.py