Fix info dircategory

Thanks to Drew Adams and Steve Berman for reporting this.

doc/org-guide.org

@@ -2616,7 +2616,7 @@ support in a file, use
 
 #+export_file_name: orgguide.texi
 
-#+texinfo_dir_category: Emacs
+#+texinfo_dir_category: Emacs editing modes
 #+texinfo_dir_title: Org Guide: (orgguide)
 #+texinfo_dir_desc: Abbreviated Org mode manual
 

doc/org-manual.org

@@ -21060,7 +21060,7 @@ modify this GNU manual."
 
 #+export_file_name: org.texi
 
-#+texinfo_dir_category: Emacs
+#+texinfo_dir_category: Emacs editing modes
 #+texinfo_dir_title: Org Mode: (org)
 #+texinfo_dir_desc: Outline-based notes management and organizer