l10n: git.pot: v2.20.0 round 1 (254 new, 27 removed)

Generate po/git.pot from v2.20.0-rc0-23-gbb75be6cb9 for git v2.20.0 l10n
round 1.

Signed-off-by: Jiang Xin <[email protected]>

Author: jiangxin