Add extra check on project close for any layer in edit mode with unsaved edits

[dakcarto]

• Ensures user has opportunity to save provider edits
• Make project dirty if any unsaved edits found
• Add red notification to project save prompt dialog, and set Cancel to default
• Fix for [sipify] keep Docstrings for template based classes #6054 and [processing][FEATURE][needs-doc] load default script from template backport to 3.0 #6732

[dakcarto]

Hi,

I sent this in as a pull request because I thought someone might desire it to be implemented in a different way (like always making the project dirty on provider edit). I think it is good as is, since it communicates to the user specifically what they may lose if continuing to close a project.

Editing a layer's provider data does not always seem to make the project dirty, then users may lose edits on unprompted project close. Since editing provider data is separate to edits a user may have done specifically to the project, when prompted that the project is dirty on close, the user may not realize why the project needs saved (this fixes that by adding a notification).

Also, after such a dirty-project-only prompt, saving and closing the project will NOT save the provider edits, leading to unanticipated loss of editing. I do not think attempting to auto-save provider data edits on project close is a good idea. Merely warning the user that the issue exists should suffice.

I'll wait a couple of days. If no one has any issue with it, I'll merge it.

[dakcarto]

Added with direct commit 21370d9