Typo fix

[brett-talko]

Fix type of mention → mentions in the GitHup exercise instructions

[ceddlyburge]

Hi Brett, can you remove the changes to exercises/practice/grains/.docs/instructions.md in this PR.

The change isn't related to the title of the PR, and also that text is generated from https://github.com/exercism/problem-specifications/blob/main/exercises/grains/instructions.md

If you still want to make that change, please open a pr in the problem-specifications repo

[brett-talko]

Hi Brett, can you remove the changes to exercises/practice/grains/.docs/instructions.md in this PR.

The change isn't related to the title of the PR, and also that text is generated from https://github.com/exercism/problem-specifications/blob/main/exercises/grains/instructions.md

If you still want to make that change, please open a pr in the problem-specifications repo

Yes, sorry, I accidentally made another change but I thought it wouldn't get caught up in this pull request. I'm still new to using github.

Update: Okay. I've reedited the file and committed it. Let me know if there are any problems. Cheers.

[ceddlyburge]

Thanks Brett :)