Unicode::UCD: Correct wrong pod info

 This was erroneous.  Extra clarifications are also added.
Unicode::UCD: Move function in file.

This is in preparation for making this function public, and it should be
listed in the pod later than it otherwise would be.
Unicode::UCD Clarifications in pod

There are no "missing" values in inversion maps; there is a default
value returned for each one.  So change the example variables' names.
Plus another sentence rewording for clarity.
Make Unicode::UCD::search_invlist() available

This commit documents this function, removing the initial underscore
from its name.  (And it hardens input checking.)
regcomp.c: Actually emit proper warning

Before this commit, /\g/ raised the wrong warning
    Reference to invalid group 0
This rearranges the code so that the proper warning is emitted.
    Unterminated \g... pattern
perldiag: Describe \g syntax error

Commit 779fedd7c3021f013726c8f53cb9e66c54637ebf added a warning,
which is nearly identical to an existing one, but didn't change the
description of the existing one to encompass both.  This rectifies that.
typo fixes for root level scripts

Add David Steinbrunner to AUTHORS.
Update pod issues database.
typo fixes for regen scripts
typo fix for vms script
Correct known_pod_issues.dat.
Provide alternate email address for jkeenan.
Refactor the "check categories and severity" logic in diag.t

Move the "todo" bailout as early as possible, before any work is done.
Replace C<use 5.01> [sic] with C<use feature 'state'>, as this makes the
intent much clearer.
Use parenthesis for like() and is() as this is consistent with the rest of the
test, and permits a simplification of the BEGIN handling.
Avoid VMS running autodoc.pl twice for no reason.

Previous descrip_mms.template carried separate rules to build perlintern.pod
and perlapi.pod, each of which caused autodoc.pl to run. autdoc.pl builds
both files when it runs, so this was duplicate work.
In t/porting/diag.t, use TestInit to chdir and set up @INC.

Also eliminate the $|=1, as it's really not necessary for tests that neither
fork nor shell out to other processes.
t/porting/diag.t now uses regen/embed_lib.pl to parse embed.fnc

Previously it had its own custom parsing code for embed.fnc.
In regen/regen_lib.pl, add 'Pod' as a third supported 'language'.

Pod needs a commenting style distinct from C and Perl. (ie the empty string)
Refactor autodoc.pl to use regen_lib.pl to generate file headers & footers.

This reduces duplication of code that generates '-*- buffer-read-only: t -*-',
'ex: set ro:' etc.
autodoc.pl now uses regen/embed_lib.pl to parse embed.fnc

Previously it had its own custom parsing code for embed.fnc.
Refactor autodoc.pl to read MANIFEST line by line, instead of slurping it.
Sync Module-CoreList version in Maintainers.pl