Fixed typo in git action error

[effleurager]

Fixed typo in message shown when git cannot open a file which has been deleted.

[msftclas]

Hi @effleurager, I'm your friendly neighborhood Microsoft Pull Request Bot (You can call me MSBOT). Thanks for your contribution!

This seems like a small (but important) contribution, so no Contribution License Agreement is required at this point. Real humans will now evaluate your PR.

TTYL, MSBOT;