`make docs-auto` should ignore editor temp files and stuff.

[lengau]

Ideally we'd get this: sphinx-doc/sphinx-autobuild#140

But until then we should ignore things like *.[a-z]+-swp

[lengau]

@medubelko @jahn-junior I'd love your opinions on what else to ignore here. The editor swap files are a personal bugbear to me because kate creates them whenever I type a character, but if we're doing this we should include anything else. Maybe worth asking the TAs in general about anything they ignore?

[medubelko]

Recent discussions among TA have listed Vim, NeoVim, emacs, Kate, and VS Code. I would probably add VS to that list. It might be worthwhile to poll any leftover Mac users. I'm not sure what makes most sense for Linux dev on Mac these days.