docs: remove all mentions of --markmatch and 'set markmatch'

IMPROVEMENTS

@@ -3,7 +3,6 @@ Improvements in GNU nano
 
 Since 5.0:
   - Option --minibar reduces the interface to a bottom bar with basic info.
-  - Option --markmatch marks the search result, for better visibility.
   - The cursor skips over combining characters, <Del> deletes them together
     with the character they combine with, but <Bsp> deletes them separately.
   - For using libmagic the option --magic or -! or 'set magic' is required.

doc/nano.1

@@ -329,12 +329,6 @@ Make Ctrl+Right and Ctrl+Delete stop at word ends instead of beginnings.
 .BR \-z ", " \-\-suspendable
 Allow the user to suspend the editor (with \fB^Z\fR by default).
 .TP
-.BR \-^ ", " \-\-markmatch
-After a search, set the mark at the end of the found match
-(if there is any) so that it gets highlighted.  This makes
-the match more visible, but also allows deleting the match
-with a single keystroke.
-.TP
 .BR \-% ", " \-\-stateflags
 Use the top-right corner of the screen for showing some state flags:
 \fBI\fR when auto-indenting, \fBM\fR when the mark is on, \fBL\fR when

doc/nano.texi

@@ -468,13 +468,6 @@ Make Ctrl+Right and Ctrl+Delete stop at word ends instead of beginnings.
 Enable the ability to suspend @command{nano} using the system's suspend
 keystroke (usually @kbd{^Z}).
 
-@item -^
-@itemx --markmatch
-After a search, set the mark at the end of the found match
-(if there is any) so that it gets highlighted.  This makes
-the match more visible, but also allows deleting the match
-with a single keystroke.
-
 @item -%
 @itemx --stateflags
 Use the top-right corner of the screen for showing some state flags:
@@ -929,12 +922,6 @@ try using libmagic to determine the applicable syntax.
 (Calling libmagic can be relatively time consuming.
 It is therefore not done by default.)
 
-@item set markmatch
-After a search, set the mark at the end of the found match
-(if there is any) so that it gets highlighted.  This makes
-the match more visible, but also allows deleting the match
-with a single keystroke.
-
 @anchor{@code{set matchbrackets}}
 @item set matchbrackets "@var{characters}"
 Specify the opening and closing brackets that can be found by bracket

doc/nanorc.5

@@ -176,12 +176,6 @@ try using libmagic to determine the applicable syntax.
 (Calling libmagic can be relatively time consuming.
 It is therefore not done by default.)
 .TP
-.B set markmatch
-After a search, set the mark at the end of the found match
-(if there is any) so that it gets highlighted.  This makes
-the match more visible, but also allows deleting the match
-with a single keystroke.
-.TP
 .BI "set matchbrackets """ characters """
 Specify the opening and closing brackets that can be found by bracket
 searches.  This may not include blank characters.  The opening set must

doc/sample.nanorc.in

@@ -79,9 +79,6 @@
 ## Fall back to slow libmagic to try and determine an applicable syntax.
 # set magic
 
-## After a search, set the mark at the end of the found match (if any).
-# set markmatch
-
 ## The opening and closing brackets that can be found by bracket
 ## searches.  They cannot contain blank characters.  The former set must
 ## come before the latter set, and both must be in the same order.