bug#73484: 31.0.50; Abolishing etags-regen-file-extensions

[Eli Zaretskii <eliz@gnu.org>]

> Cc: 73484@debbugs.gnu.org, spwhitton@spwhitton.name
> Date: Sun, 29 Sep 2024 11:25:45 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> 
> I understand that we need to disable the Fortran and C fallbacks to
> avoid false positives, but what do we want to do if the fallbacks are
> disabled and no suitable language parser is found using the file name?
> Just skip the file and do nothing? emit a warning? something else?

Wait a minute... we already have "--language=none", which means only
do regexp processing, if any.  If no regexps were specified, 'none'
produces a single entry for a file, stating just its name, like this:

  ^L
  foo,0

where ^L is a literal \f character.  Is the intent here to prevent
even that from being written to TAGS?  If not, then we don't need any
new command-line option; instead, etags-regen could simply pass the
"--language=none" option before each file with no extension, and be
done, no?

Or maybe this is "the missing link" between this and the shebang
processing?