new 'mention_decor' option

Somewhat similar to 'mention_walls', 'mention_decor' is a way to
request additional feedback when moving around the map.  It reports
furniture or unusual terrain when you step on that.  Normally stepping
on furniture only mentions it when it is covered by object(s).  And
moving onto (rather than into) water or lava or ice doesn't bother
saying anything at all.  With the new option set there will be a
message.  It uses Norep so won't repeat when moving from one water
spot to another or one lava spot to another or one ice spot to another
unless there has been at least one intervening message.  There is also
a one-shot message when moving from water or lava or ice onto ordinary
terrain (not Norep, just once since there's no land to land message).

Having the verbose flag Off doesn't inhibit these new messages but it
does shorten them: "A fountain." instead of "There is a fountain here."

The Guidebook gets a new subsection "Movement feedback" of the "Rooms
and corridors" section and it covers more than just 'mention_decor'.
As usual, Guidebook.tex is untested.

'mention_decor' persists across save/restore, so 'struct flags' has
changed and EDITLEVEL is being bumped, hence save files are invalided.

doc/Guidebook.tex

@@ -1966,6 +1966,90 @@ If a shop is ``closed for inventory,'' it will not open of its own accord.
 Shops do not get restocked with new items, regardless of inventory depletion.
 \end{itemize}
 
+%.hn 2
+\subsubsection*{Movement feedback}
+
+%.pg
+Moving around the map usually provides no feedback--other than drawing the
+hero at the new location--unless you step on an object or pile of objects,
+or on a trap, or attempt to move onto a spot where a monster is located.
+There are several options which can be used to augment the normal feedback.
+
+%.pg
+The
+{\it pile\verb+_+limit\/}
+option controls how many objects can be in a pile--sharing the same map
+location--for the game to state ``there are objects here''
+instead of listing them.
+The default is {\tt 5}.
+Setting it to {\tt 1} would always give that message instead of listing
+any objects.
+Setting it to {\tt 0} is a special case which will always list all
+objects no matter how big a pile is.
+Note that the number refers to the count of separate stacks of objects
+present rather than the sum of the quantities of those stacks (so
+{\tt 7 arrows} or {\tt 25 gold pieces} will each count as 1 rather
+than as 7 and 25, respectively, and total to 2 when both are at the
+same location).
+
+%.pg
+The \{\tt nopickup} command prefix (default `\{\tt m}') before
+a movement direction can be used to step on objects without attempting
+auto-pickup and without giving feedback about them.
+
+%.pg
+The
+{\it mention\verb+_+walls\/}
+option controls whether you get feedback if you try to walk into a wall
+or solid stone or off the edge of the map.
+Normally nothing happens (unless the hero is blind and no wall is shown,
+then the wall that is being bumped into will be drawn on the map).
+This option also gives feedback when the various rush or run variations
+of movement stop for some non-obvious reason.
+
+%.pg
+The
+{\it mention\verb+_+decor\/}
+option controls whether you get feedback when walking on ``furniture.''
+Normally stepping onto stairs or a fountain or an altar or various other
+things doesn't elicit anything unless it is covered by one or more objects
+so is obscured on the map.
+Doorless doorways and open doors aren't considered worthy of mention;
+closed doors (if you can move onto their spots) and broken doors are.
+Assuming that you're able to do so, moving onto water or lava or ice
+will give feedback if not yet on that type of terrain but not repeat it
+(unless there has been some intervening message) when moving from water
+to another water spot, or lava to lava, or ice to ice.
+Moving off of any of those back onto ``normal'' terrain will give one
+message too, unless there is feedback about one or more objects, in which
+case the back on land circumstance is implied.
+
+%.pg
+The
+{\it confirm\/}
+and
+{\it safe\verb+_+pet\/}
+options control what happens when you try to move onto a peaceful monster's
+spot or a tame one's spot.
+
+%.\" getting away from "Movement feedback" here; oh well...
+%.pg
+The {\tt nopickup} command prefix (default `{\tt m}' is
+also the move-without-attacking prefix and can be used to try to step
+onto a visible monster's spot without the move being considered an attack
+(see the {\it Fighting\/} subsection of {\it Monsters\/} below).
+The `{\tt fight}' command prefix (default `{\tt F}';
+also `{\tt -}' if
+{\it number\verb+_+pad\/}
+is on) can be used to force an attack, when guessing where an unseen
+monster is or when deliberately attacking a peaceful or tame creature.
+
+%.pg
+The
+{\it run\verb+_+mode}
+option controls how frequently the map gets redrawn when moving more
+than one step in a single command (so when rushing, running, or traveling).
+
 %.hn 1
 \section{Monsters}
 
@@ -3489,6 +3573,11 @@ Enable mail delivery during the game (default on).  Persistent.
 An obsolete synonym for ``{\tt gender:male}''.  Cannot be set with the
 `{\tt O}' command.
 %.lp
+\item[\ib{mention\verb+_+decor}]
+Give feedback when walking on various dungeon features such as stairs,
+fountains, or altars which are ordinarily only described when covered
+by one or more objects (default off).  Persistent.
+%.lp
 \item[\ib{mention\verb+_+walls}]
 Give feedback when walking against a wall (default off).  Persistent.
 %.lp