bug#59954: 29.0.50; flymake-reporting-backends documentation could use some work

[Stefan Kangas]

>From reading its documentation, I don't understand what the
`flymake-reporting-backends' command does.

The docstring of `flymake-reporting-backends' says:

    Compute reporting Flymake backends in current buffer.

It is also not really explained in (info "(flymake) Troubleshooting").
More precisely, I think it must be spelled out how it's different from
`flymake-running-backends', and in which situations one would want to
use one or the other.

I understand that the "reporting" ones are basically the union of the
running and disabled ones, right?  But why are they considered
"reporting"?  That is not immediately clear to me.  Surely if they are
disabled, they are *not* reporting?  This could use some explanation.

Also, why does the docstring of `flymake-running-backends' and
`flymake-disabled-backends' talk about "computing backends", instead of
simply saying that it "displays" the running/disabled backends?

On a side note, and not necessarily part of this bug report, it would
also be useful with some documentation that says to find out more about
a particular back-end.  Currently, I guess `C-h f' is the recommended
way to do that?