Add file format popup mac

[terhechte]

This fixes #998 by adding a file format popup. A couple of caveats (as also explained in my comment here:

• MacOS usually shows these for NSDocument based apps. In order to have a similar experience, we have to build our own view hierarchy. This might not be pixel perfect similar to, say, how TextEdit does it.
• The implementation does not return the selected save path and the selected file format. Instead, the save path will be mutated based on the selected file format. So if the user enters "example.pdf" as the path and set set file format to "Jpg" the result will be that the path returned from calling the save panel is "example.jpg".
• The string File Format: is currently hard coded into the implementation. This is fine but will break with localization. There's no way to retrieve the operating system resource that is used in apps like TextEdit.

This is what it looks like:

[cmyr]

Cool, this looks good! A few comments inline, and CI is complaining in a few places, but all trivial things. Thanks!

[cmyr]

Suggested change

	// AppKit has a build-in file format accessory view. However, this is only
	// AppKit has a built-in file format accessory view. However, this is only

[cmyr]

This is interesting. our architecture does not expect druid-shell to ever need to be locale aware; the idea is that localization will happen higher up in the stack, with correctly localized strings passed in to druid-shell where needed. I'm not sure how best to do that here, though. For the time being I'm happy to punt on this, but we will want to revisit it eventually..

[cmyr]

Great, thanks!

It looks like we used to expose the path field through a getter, but I think having both of these be pub is reasonable.

[cmyr]

Okay, CI is failing because FileInfo is created in the other backends, and they aren't setting the new field. Other than that this looks ready to merge. #1846 should merge without any problem 🤞, so I think once that's merged you'll be a "contributor" and CI will run automatically on this when you make changes; if it doesn't just ping me or someone else in order to click the "run" button. 😅

[terhechte]

Thanks! @cmyr I'll have a look now. Sorry for the long delay, the last couple of days were rather busy.

[cmyr]

I think this needs to be rebased to fix the clippy lints. :(

[terhechte]

@cmyr I did a rebase, cargo clippy runs fine on my system. I hope this can be merged soon :-)

I guess there is no easy way to run the Windows test suite locally except by booting up a Windows machine or running a VM, right?

[cmyr]

Great, thank you very much @terhechte!