Show item tutorial msg when picking item actions

This assumes that the menu of item actions is assembled as the player
asks for it, since it shows in the function that builds it.

I wanted it to go where the menu is shown, but apparently that lives in
the front-end interface, so this will have to do for now.
Unify style of help menu entries

The client help options now share the direct, lowercase style of the
rest of the entries.

All help menu entries are a bit shorter too.
Split tutorial review menu with section headers

This makes finding tutorial mode messages much, much easier.
Safeguard building of tutorial menu when empty

If the player somehow is able to bring up the tutorial review menu
before any messages have been shown, show a suitable message instead of
trying to show a menu with no items.
Indicate latest message in tutorial review menu

The text [LATEST!] now appears after the last tutorial message shown in
tutorial mode, making it much easier to see an accidentally skipped or
skimmed message.
Cut redundancy in tutorial messages

This removes repeated mentions of the discoveries list, the effect of
armor on spellcasting, hunger status, how AC works and other things,
reducing the total tutorial message lines by about 50 and only showing
new players info when they need it.
CS374: Fix non-existing potions in color alchemy

If two potions mixed with color alchemy produced a non-existing output
potion, it would produce that instead of one of the random alchemy
results.

Compared to UnNetHack, this omits some defensive programming put in
places that will almost certainly annoy the player, e.g. a warning in
the xname2 function.
Fix death tutorial msg accidentally commented line

Extended commands are denoted with a hash, but a hash at the start of a
line denotes a comment in the quest text file!  This rewords the message
a bit to change the position of the hash to work around this problem.
CS375: Add tutorial message for dungeon overview

Compared to UnNetHack, the message is adjusted to account for NitroHack
allowing level memory to be viewed and for the new tutorial message
convention of listing relevant commands at the bottom.
CS376: Replace impossible() w/ warning() in worm.c
CS378: Make conflict anger the Black Marketeer

Also fix a silly amount of white space trailing a nearby line.
CS381: Acknowledge Pi Day

On March 14, cream pies get a different name (look up the flavor text!)
and YAFM when they are thrown and hit you.
CS382: Hide "You are protected" when AC unchanged

When enlightened, wearing e.g. +1 and -1 rings of protection will no
longer say "You are protected."
CS383: Fix psychic blast and monster tinfoil hat

The original changeset is actually "Pacify most compiler warnings", but
this clarifies (and interprets differently) a complex condition I had to
punt on when porting the Tinfoil Hat patch (commit b7a73e7616).
Edit Random-Appearance Items, Stairs tutorial msgs

Random-Appearance Items fixed to match the style of other messages, and
Stairs removes a redundant comment about the level 1 stairs leading out
of the dungeon.
Suppress message when cancelling direction prompt

Using an item in a direction and changing your mind by pressing escape
now no longer displays "What a strange direction!"