AnnotateInput: redesign submit button
I still think it is important that it looks less like a send button of the Telegram messenger. I can't really make a better suggestion than what I already suggested again and again:
Paper-plane icon in a (light) grey color, does not need to be placed inside the input field. I would like to at least try if it is really too hard to see or difficult to use.
I don't think that it needs to be consistent with the "submit" button that is used when you attach an image or video or audio recording (as I said before).
I'm open for other suggestions, also regarding the icon. Goal should be to move a bit away from the messenger association, underscore that it is all about "text, text, text". However, I know that sticking to the pape-plane icon seems to be a good idea in general, because it is almost universally understood.
This issue is linked to #990 (closed).