Closes files opened from the side bar when their corresponding project is closed

[igordsm]

Closes #774 : when a project folder is closed all files opened by clicking in the sidebar are closed too. Files opened by using the "open" button in the toolbar (or Ctrl+O) remain even if they belong to a project folder that was closed.

Keep in mind that this is my first experience with Vala. I am aware that my solution is probably not the best, but I am willing to make it so.

Thank you for your contributions on this and hope to hear from you soon.

[tintou]

Thanks for your contribution, there are a few things to change and this can be ready to go

[igordsm]

@tintou thank you for your revisions. I have accepted them and fixed the last linting error. CI now passes.

[jeremypw]

@igordsm @tintou The PR #833 has been submitted addressing the same issue, but in a simpler way. Although it has some issues these are easily fixed. Are there any advantages to your approach?

[igordsm]

@jeremypw When I created this PR I wanted to separate files opened from the project bar and files opened via the Open toolbar button. So this would not close a file that belongs to a project that is being closed but was opened via the toolbar. It is much more complex than the other proposal, so it is up for discussion if this additional complexity is worth it. I am not sure, honestly, as this seems like an edge case.

[jeremypw]

@igordsm Yes, it seems unlikely that a user would open a project file manually when it easier to open it from the sidebar. Even then, if you close a project folder you are kind of saying "I don't want to work on the files in this project anymore" so if one stays open it could be unexpected. So personally I don't think it is worth the extra complexity.

One refinement that could be useful is a context menu option for expandable folders "Close all documents in this folder" (easily implemented based on #833) but that is for another PR.

[igordsm]

Closing this in favour of #833 .