some spelling and inconsistency corrections; comments and elsewhere

doc/Guidebook.mn

@@ -47,7 +47,7 @@
 .ds f0 \*(vr
 .ds f1 \" empty
 .\"DO NOT REMOVE NH_DATESUB .ds f2 Date(%B %-d, %Y)
-.ds f2 December 03, 2025
+.ds f2 December 11, 2025
 .
 .\" A note on some special characters:
 .\" \(lq = left double quote
@@ -3537,7 +3537,7 @@ is a section marker (the closing \(oq\f(CR]\fP\(cq can be followed
 by whitespace and then an arbitrary comment beginning with \(oq\f(CR#\fP\(cq).
 The text between the square brackets is the section name.
 Section markers are only valid after a CHOOSE directive and their names
-are case insensitive.
+are case-insensitive.
 Lines after a section marker belong to that section up until another
 section starts or a marker without a name is encountered or the file ends.
 Lines within sections are ignored unless a CHOOSE directive has selected
@@ -4671,7 +4671,7 @@ or you are making screenshots or streaming video.
 Using the
 .op statuslines:3
 option is recommended so that there will be more room available for
-status information, unless you're using nethack's \fIQt\fP interface
+status information, unless you're using NetHack's \fIQt\fP interface
 or your terminal emulator window displays fewer than 25 lines.
 Persistent.
 .lp "silent  "