docs: mention the new 'set highlightcolor' option

doc/nano.texi

@@ -892,6 +892,11 @@ if your terminal can do those.
 Draw a vertical stripe at the given column, to help judge the width of the
 text.  (The color of the stripe can be changed with @code{set stripecolor}.)
 
+@item set highlightcolor [bold,][italic,]@var{fgcolor},@var{bgcolor}
+Use this color combination for highlighting a search match.
+The default value is @t{black,yellow}.
+@xref{@code{set functioncolor}} for valid color names.
+
 @item set historylog
 Save the last hundred search strings and replacement strings and
 executed commands, so they can be easily reused in later sessions.

doc/nanorc.5

@@ -146,6 +146,11 @@ See \fBset titlecolor\fR for more details.
 Draw a vertical stripe at the given column, to help judge the width of the
 text.  (The color of the stripe can be changed with \fBset stripecolor\fR.)
 .TP
+.B set highlightcolor \fR[\fBbold,\fR][\fBitalic,\fR]\fIfgcolor\fB,\fIbgcolor\fR
+Use this color combination for highlighting a search match.
+The default value is \fBblack,yellow\fR.
+See \fBset titlecolor\fR for valid color names.
+.TP
 .B set historylog
 Save the last hundred search strings and replacement strings and
 executed commands, so they can be easily reused in later sessions.

doc/sample.nanorc.in

@@ -203,13 +203,15 @@
 ## of a single character, and without affecting the cutbuffer).
 # set zap
 
-## Paint the interface elements of nano.  These are examples;
-## by default there are no colors, except for errorcolor.
+
+## Paint the interface elements of nano.  These are examples; there are
+## no colors by default, except for errorcolor and highlightcolor.
 # set titlecolor bold,lightwhite,blue
 # set promptcolor lightwhite,lightblack
 # set statuscolor bold,lightwhite,green
 # set errorcolor bold,lightwhite,red
 # set selectedcolor lightwhite,magenta
+# set highlightcolor black,lime
 # set stripecolor ,yellow
 # set scrollercolor cyan
 # set numbercolor cyan
@@ -222,6 +224,7 @@
 # set statuscolor bold,lightwhite,magenta
 # set errorcolor bold,lightwhite,red
 # set selectedcolor lightwhite,cyan
+# set highlightcolor black,orange
 # set stripecolor ,yellow
 # set scrollercolor magenta
 # set numbercolor magenta