doc/nethack.6: Revise scoreboard mode synopsis

Set it as a hanging paragraph, as is idiomatic for Unix command
synopses.  Tighten formatting: set synopsis syntax characters adjacently
to operands.  Since viewing the scoreboard is a separate mode of
operation, arrange first the options that select this mode.[1]  Also
drop explicit line breaks, permitting synopsis to exercise the
configured line length of the selected output device.

Before and after, as rendered with Solaris 10 troff:

-     nethack [ -d|--directory directory ] -s|--scores [ -v ]
-     [ -p profession ] [ -r race ] [ player-name ...]
+     nethack {-s|--scores} [-d|--directory directory] [-v]
+          [-p profession] [-r race] [player-name ...]

Before and after, as rendered with groff, mandoc, and Heirloom Doctools
troff:

-     nethack [ -d|--directory directory ] -s|--scores [ -v ]
-     [ -p profession ] [ -r race ] [ player‐name ...]
+     nethack {-s|--scores} [-d|--directory directory] [-v] [-p profession]
+            [-r race] [player‐name ...]

Not shown: Literal text is in bold, and option arguments in italics.

[1] See, for example,
<https://pubs.opengroup.org/onlinepubs/9799919799.2024edition/utilities/compress.html>.

doc/nethack.6

@@ -128,27 +128,17 @@ Also
 |
 .BR \-W | \-Wiz
 ]
-.PP
+.HP
 .B nethack
-[
-.BR \-d | \-\-directory
-.I directory
-]
-.BR \-s | \-\-scores
-[
-.B \-v
-]
-.br
-[
-.B \-p
-.I profession
-]
-[
-.B \-r
-.I race
-]
-[
-.I player-name\*_\c
+.RB { \-s | \-\-scores }
+.RB [ \-d | \-\-directory\*_\c
+.IR directory ]
+.RB [ \-v ]
+.RB [ \-p\*_\c
+.IR profession ]
+.RB [ \-r\*_\c
+.IR race ]
+.RI [ player-name\*_\c
 \&.\|.\|.]
 .PP
 .B nethack