Docs incorrectly list override-git-commit instead of override_git_commit

[akonradi-signal]

Describe the bug The documentation says that override-git-commit: [hash] can be used in about.toml to override the commit used to find the license file. That's not correct; the field is called `override_git_commit.

[Jake-Shadle]

The docs are correct, the code was not, the field is now renamed to be what it was supposed to be, thanks for raising this issue.