GUI extension - some methods are missing the floating/!floating tag

[Trinitou]

in gui.h: Some methods don't have the floating / !floating tag although they are only for one of the modes, e.g

• can_resize
• adjust_size
• set_size
• request_resize?

Instead it is mentioned in the comment that the method is only for embedded windows. I think only the tags should be used instead of the comments.

[abique]

Maybe you want to make a PR for that?

[Trinitou]

Maybe you want to make a PR for that?

If i find the time, I'll do. If somebody else is faster, no problem 😉

[Trinitou]

Maybe you want to make a PR for that?

-> #315