[Wildcard Variables] Update UNUSED_CATCH_STACK reporting

[pq]

Like UNUSED_LOCAL_VARIABLEs, we'll want to flag binding __s in UNUSED_CATCH_STACK.

For example we do not report on the __ below

try {

} catch(e, __) { }

(but should).

/fyi @kallentu

[kallentu]

Documenting some thoughts from a chat @pq and I had:

Once we flag the binding __s, we'll report UNUSED_CATCH_STACK which has a quick fix to remove the catch stack trace parameter.

try {
} catch(e, _) { 
  // ..
  // e used somewhere 
}

In this scenario with a wildcard, the stack trace isn't used, but could we not write the above as the following code? It's a small thing, but maybe it's nice to have a quick fix for this?

try {
} catch(e) { 
  // ..
  // e used somewhere 
}

@lrhn mentioned this in #55723 (comment), but shrug I feel like it'd be nice.

[lrhn]

If there is a quick-fix to remove the unnecessary , _, then it's probably fine to warn about it.
I don't expect many people to see analyzer warnings, and not have access to the quick-fixes.