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

runtime/lua/man.lua

@@ -415,7 +415,7 @@ end
 local function set_options(pager)
   vim.bo.swapfile = false
   vim.bo.buftype = 'nofile'
-  vim.bo.bufhidden = 'hide'
+  vim.bo.bufhidden = 'unload'
   vim.bo.modified = false
   vim.bo.readonly = true
   vim.bo.modifiable = false