Add missing message channels to options_guide.txt
Fix red devil hop attack order and messaging (#7573)

Have them strike just before the hop, when they are adjacent to the foe
and therefore guanteed to have line of effect.  Furthermore, print the
"hops backward" message (which should only happen for successful hops)
with the correct non-"it" noun whenever the monster was visible at
*either* end of the hop, not just the destination.
Add Naruni and BlackSheep to CREDITS.txt
Add frogor to CREDITS.txt
Reworked boots of the Assassin

Allows you to stab with short blade level bonuses, and provides radius 4
monster detection.
Update options_guide's advice on where to ask for help
Suppress detection from Boots of the Assassin.

Since the stab enhancement is flavoured as non-magical, allow it to work
even while suppressed.
Constify, simplify, fix some types, and reformat.
Fix an infinite loop with insane friendlies attacking the player.

mon-act thinks the attack will succeed, melee_attack denied it.  Since
insanity is a form of confusion, let's allow the monster to attack you.

Also, don't set the foe to the player in such a case: attack just once,
like it's done against monsters.
Fix a crash if a boulder beetle dies due to damage it deals.

In this case, this was an inner flame explosion, which we really should
make a fineff.
Remove a crashy trap from an abyssal vault.

I guess I could instead make such traps not crash, but since the only trap
in the Abyss comes from a single vault, and is a mechanical one to boot,
here it goes.
Move the handling of 'B' vault altars to the proper function.

That's what the comment requested.  I think 'C' should be moved, too --
it is random, unlike anything else in that function.
Get rid of traps in a number of vaults.

This is a step towards complete removal of mechanical traps.  The few traps
that are supposed to remain don't work well in the niche once filled by
mechanical ones.  And, most vaults placed them in fixed or almost fixed
places.

This is only a start of the work, there are some cases that need discussing.
Delete three empty description files.

They had only quotes.
Colour large rocks differently than stones and sling bullets.

Hardly ever the same character will want both.
Add reminder comments about some arrays that parallel enums.
Don't break chaos and evasion brands in mapdefs on major tag bump.
A quote for crocodile.
Fix reversed feature names for sealed stairs.
Fix a couple of major save tag bump bugs.