bug#46775: 27.1; ERC: Track: Modified channels doc and `erc-track-find-face' fixes

[Olivier Certner <ocert.dev@free.fr>]

> The updates to the doc string here are likewise superb and make things
> crystal clear.

Thanks!
 
> only 51% sure you meant s/necessary means/necessarily means/ in that

I fixed the typo in the updated patch.

> Regarding this module generally, it's definitely another one whose
> layout confuses me. For example, I guess we can't add keymaps to minor
> modes defined with `define-erc-module'? IOW, why the
> `erc-track-minor-mode-map' instead of a `erc-track-mode-map'?

The trick is that `erc-track-minor-mode' may be enabled or disabled 
independently of the whole module. In particular, it may not be activated at 
all if the (global) keybindings it wants to install, which don't abide by the 
rules for minor modes maps, are already bound at the time of module's 
activation.

> I'm also confused by the 001 RPL_WELCOME hook, but for now, I'll just assume
> it's a vestige of a simpler time when `erc-user-is-active' looked different
> and maybe did more. Or (more likely) there's something I'm not seeing
> just yet.

`erc-user-is-active' seems in fact to be used for more than one purpose. In 
particular, it also triggers an update of channels in the mode line. What's 
exactly the problem with hooking on 001?

> Anyway, I mention this stuff because you may be the best/only
> qualified person to address such concerns at present. Would you be
> willing to audit this file for redundancy/cruft/obsolescence at some
> point before the next release? Thanks.

Depending on available time and precise concerns that you may have, yes.

There is a lot of room for improvement in this module. In particular in 
determining how some user is "active" (none of the current possibilities 
really suits my needs).

-- 
Olivier Certner