bug#54159: 29.0.50; `toggle-input-method' needs more user feedback

[Eli Zaretskii]

> From: Case Duckworth <acdw@acdw.net>
> Date: Fri, 25 Feb 2022 11:12:30 -0600
> 
> 
> The other day I had some issues with typing that I could not figure out
> the meaning of.  I checked my messages buffer, C-h m, etc., and nowhere
> did I figure out that the issue was actually that I'd typed C-\
> (fatfingered it) and toggled the input method to RFC 1345, which caused
> & to trigger different inputs.
> 
> Shouldn't `toggle-input-method' include a message to the user?

It would be an annoyance, because when people use an input method they
typically toggle it on and off quite frequently.  Moreover, input
method can also be toggled when typing at the prompt in the minibuffer
(for example, when searching with Isearch or typing a file name at the
prompt of "C-x C-f"), in which case displaying a message there will
cause surprising effects.

The input method is reflected on the mode line, and we think that's
enough.