Documentation/git-pull.txt: Add subtitles above included option files

Signed-off-by: Jari Aalto <jari.aalto@cante.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-pull.txt

@@ -26,6 +26,10 @@ Also note that options meant for 'git-pull' itself and underlying
 
 OPTIONS
 -------
+
+Options related to merging
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
 include::merge-options.txt[]
 
 :git-pull: 1
@@ -47,6 +51,9 @@ unless you have read linkgit:git-rebase[1] carefully.
 --no-rebase::
 	Override earlier --rebase.
 
+Options related to fetching
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
 include::fetch-options.txt[]
 
 include::pull-fetch-param.txt[]