bug#52245: Wishlist: cycle input methods

[Eli Zaretskii]

> From: Robert Pluim <rpluim@gmail.com>
> Date: Thu, 02 Dec 2021 16:49:56 +0100
> Cc: 52245@debbugs.gnu.org
> 
> `default-input-method' is currently either nil or an input method to
> use for `toggle-input-method'. Extend it to allow it to be a list to
> cycle through, containing either
> 
> - input-method symbols
> - the symbol 'input-method-history
> 
> So you could have eg
> 
> '(latin-prefix input-method-history czech)
> 
> If input-method-history contained 'polish, then cycling would go
> 
> latin-prefix -> polish -> czech -> no input method

That's okay, but we should have this as an optional behavior, so that
people could still toggle only between some input method and no input
method with a single C-\, even if they defined a list of them.