Normalize "i" and "q" bindings inn neomutt

It is simply annoying to have sometimes "i" and always "q" to exit a
menu (view) in neomutt. Instead this change normalizes that by removing
_any_ functionality from "q", except of quitting neomutt on the index.

In turn "i" becomes the only binding to exit a menu.

This change improves actually 2 things for me, first the coherence and
second the "i" is actually easier to reach and therefore more pleasant
to exit quickly from the attachments then via "q".

.config/mutt/muttrc

@@ -32,6 +32,8 @@ bind pager k previous-line
 bind pager <Backspace> previous-entry
 bind pager <Enter> next-entry
 bind pager <Return> next-entry
+bind attach i exit
+bind pager,attach q noop
 
 bind pager,index \ch sidebar-toggle-visible
 bind pager,index \cj sidebar-next