Check the commit message you just wrote before pushing. To gate every commit instead, put lingua grammar < "$1" in .git/hooks/commit-msg.
$ git log -1 --format=%B | lingua grammar
# "Fix bug where clicking the the button crash the app"
grammar: The word ‘the’ may be inadvertently doubled. Consider deleting the second instance. -> the [23,7]
grammar: The word ‘the’ may not agree with the rest of the sentence. [27,3]