feat: add button that finds missing OCR captions

[thiswillbeyourgithub]

Hi !

I decided to add a new menu button that allows to find the missing captions in the collection. Hope you like it!

You can find reference to this in the issue #17

Have a nice day and good luck on your studies!

[thiswillbeyourgithub]

I just realized that some users use the OCR in a dedicated field instead of as html code.

Do you think it would be good enough to have this button appear only if the setting is set to "tooltip" ?

[cfculhane]

Hi there, thanks for this - I'm literally in the middle of exam period, but will get this merged in a week or so. Thanks for your contribution @thiswillbeyourgithub !

[thiswillbeyourgithub]

Good luck on your exams :) The world needs more doctors that know how to code >_< !

Btw, I'm still on anki 2.1.44 so I don't really know if it works in new versions.

edit : you could also use this to automatically rerun OCR on them instead of adding a tag, I could code it it you want me to.

[thiswillbeyourgithub]

I added a new commit for a new button :)

I tested it and it seems to work fine on anki 2.1.49

Also: less false positive because .gif and .svg are ignored :)