[Feature Request] Option to download all undownloaded chapters

[Mitia99]

Why/User Benefit/User Problem

For users who want to download all chapters but can't download them at once.

What/Requirements

[gloist]

Just click the "All Chapters", It'll download the undownloaded chapters by default since there's a restriction about this issue.

[Mitia99]

@gloist In that case, I think that it will be better to replace the text "All chapters" by "All undownloaded chapters"

[gloist]

It might be, but it will just add some unecessary work ('all' if all is downloaded, else 'undownloaded'). But it won't even change the function at all.

[Caio99BR]

Maybe it need to adding something like "All chapters ('x' missing)" and/or disabling the button when all chapters are downloaded (in both options)