git-commit-mode isn't a major-mode anymore

[tarsius]

In version two of Magit, git-commit-mode isn't a major-mode anymore. It's now a minor-mode which can be combined with whatever major-mode is most suitable for the commit message format used by a project. The default is text-mode, but something like markdown-mode might also make sense in some cases.

counsel-at-git-issue-p should be adjusted accordingly. (Also there is a typo in the doc-string of that function.)

[abo-abo]

Thanks.