Git Sync documentation missing details on discarding changes

### Code of Conduct

- [X] I have read and agree to the Insomnia Docs project's [Code of Conduct](https://github.com/Kong/insomnia-docs/blob/main/CODE_OF_CONDUCT.md).

### What article on docs.insomnia.rest is affected?

https://docs.insomnia.rest/insomnia/git-sync

### What part(s) of the article would you like to see updated?

In Insomnia Synced projects there is a "discard local changes" button on the main repo menu, there is no corresponding button for Git Synced projects.

The option to do this for individual files is found within the "Commit" pop-up window, where changes to all files or individual files can be reverted, this however is not documented within this page, and the buttons themselves are invisible until highlighted so are very easy to miss.

### Additional information

_No response_

### Code of Conduct and Community Expectations

- [X] I agree to follow this project's Code of Conduct
- [X] I agree to abide by the Community Expectations

Open the affected Git Sync article at docs.insomnia.rest/insomnia/git-sync and review its existing explanation of project changes. Document how to discard changes for all files or individual files from the Commit pop-up, including that the controls may only appear when highlighted; the article should clearly explain this workflow and its difference from Insomnia Synced projects.

Written by the indexing model from the issue text.