UI: Add search button to search bar

[thansk]

Closes #529

[unixfox]

Why? There is no description.

[ChunkyProgrammer]

Related: #4098

[thansk]

Because I find that sometimes I enter something into the box and later want to submit it without my keyboard around.

I think it's generally a good idea for accessibility to make invidious usable without a keyboard.

[unixfox]

Ha ok you just added a button on the search bar.

The title is very confusing.

To be fair I quite like the way it is without any search button.

I think I good compromise would be to just have the search icon. Not the full text "Search". Like on youtube.com

[thansk]

I added an icon instead and used the aria-label for it with the translation like @ChunkyProgrammer suggested. Icon is using the currentColor so it works on dark and light theme. It's MIT licensed from heroicons.

[unixfox]

Please use the built-in icons instead: https://github.com/iv-org/invidious/blob/master/assets/fonts/ionicons.svg

[thansk]

Yeah, that makes sense, it should be good now.

[SamantazFox]

Thanks for contributing to invidious :D