fix(man.lua): hardwrapped manpage is not resized #25646

Problem:
If a manpage is opened, its hardwrapped dimensions are not recalculated
after closing then revisiting the same manpage.

Solution:
Unload the manpage when it is hidden. This forces it to be reloaded,
which forces the hard-wrapping to be recalculated when it is revisited.

Fixes: #25457