Allow multiline alt-text

Behavior suggestion/Feature request

To describe some media, it's quite useful to have line breaks as a simple formatting.

For example this picture has a dialog and dialogs usually formatted with line breaks.

I simulated it simply replacing input with textarea, don't mind the tiny image, ideally panel could increase it's height to fit both the text box and the image:

Not only that, single line alt text is unreadable on the image preview:

Some users put too much text in the description so sane limitation on preview would still be useful.

FE version: 6341a48d

It doesn't seem to be a limitation on the BE side, as Akkoma frontend fork supports multiline media descriptions.