Add sub-headings for option categories in man page.

man/epubgrep.1.adoc

@@ -2,7 +2,7 @@
 :doctype:       manpage
 :Author:        tastytea
 :Email:         tastytea@tastytea.de
-:Date:          2021-06-26
+:Date:          2021-07-02
 :Revision:      0.0.0
 :man source:    epubgrep
 :man manual:    General Commands Manual
@@ -46,6 +46,8 @@ epubgrep -C2 --status --status-interval=20 --html 'Apples' file.epub > result.ht
 
 == OPTIONS
 
+=== General options
+
 *-h*, *--help*::
 Display a short help message and exit.
 
@@ -55,6 +57,8 @@ Show version, copyright and license.
 *--debug*::
 Write debug output to the terminal and log file.
 
+=== Search options
+
 *-G*, *--basic-regexp*::
 _PATTERN_ is a POSIX basic regular expression. This is the default.
 
@@ -88,6 +92,8 @@ links. Silently skips directories that are not readable by the user.
 *-e* _PATTERN_, *--regexp* _PATTERN_::
 Use additional _PATTERN_ for matching. Can be used more than once.
 
+=== Output options
+
 *-C* _NUMBER_, *context* _NUMBER_::
 Print _NUMBER_ words of context around matches.
 
@@ -95,7 +101,6 @@ Print _NUMBER_ words of context around matches.
 Turn off colors and other decorations.
 
 *--no-filename* _WHICH_::
-
 Suppress the mentioning of file names on output. _WHICH_ is ‘filesystem’ for the
 file names on your file systems, ‘in-epub’ for the file names inside the EPUB or
 ‘all’. Chapters and page numbers will still be output.