[L10N] Kickoff for Git 2.31.0 round #2

Hi,

Git v2.31.0-rc1 has been released, and introduced 9 new messages.
Let's start a new round of git l10n based on this commit:

    l10n: git.pot: v2.31.0 round 2 (9 new, 8 removed)
    
    Generate po/git.pot from v2.31.0-rc1 for git v2.31.0 l10n round 2.
    
    Signed-off-by: Jiang Xin [off-list ref]

You can get it from the usual place:

    https://github.com/git-l10n/git-po/

As how to update your XX.po and help to translate Git, please see
"Updating a XX.po file" and other sections in "po/README" file.

--
Jiang Xin