org-agenda.el: Enhance docstrings

* lisp/org.el (org-loop-over-headlines-in-active-region):
Mention `org-agenda-loop-over-headlines-in-active-region'.

* lisp/org-agenda.el (org-agenda-do-in-region): Use the
`region' face for the selected headline.
(org-agenda-loop-over-headlines-in-active-region): Mention
`org-loop-over-headlines-in-active-region'.

lisp/org-agenda.el

@@ -8779,7 +8779,7 @@ deletes the agenda entry and don't move to the next entry."
 		       (and match (looking-at-p match))
 		       (eq level (org-get-at-bol 'level))))
 	      (org-agenda-next-item 1)
-	    (overlay-put ov 'face 'org-agenda-clocking)
+	    (overlay-put ov 'face 'region)
 	    (if (or arg force-arg) (funcall cmd arg) (funcall cmd))
 	    (when (not delete) (org-agenda-next-item 1))
 	    (delete-overlay ov)))))))
@@ -10259,7 +10259,10 @@ performed on the matching headlines within the active region.
 
 The list of commands is: `org-agenda-schedule',
 `org-agenda-deadline', `org-agenda-date-prompt',
-`org-agenda-todo', `org-agenda-archive*', `org-agenda-kill'."
+`org-agenda-todo', `org-agenda-archive*', `org-agenda-kill'.
+
+See `org-loop-over-headlines-in-active-region' for the equivalent
+option for Org buffers."
   :type '(choice (const :tag "Don't loop" nil)
 		 (const :tag "All headlines in active region" t)
 		 (const :tag "In active region, headlines at the same level than the first one" start-level)

lisp/org.el

@@ -903,7 +903,10 @@ The list of commands is: `org-schedule', `org-deadline',
 `org-todo', `org-set-tags-command', `org-archive-subtree',
 `org-archive-set-tag', `org-toggle-archive-tag' and
 `org-archive-to-archive-sibling'.  The archiving commands skip
-already archived entries."
+already archived entries.
+
+See `org-agenda-loop-over-headlines-in-active-region' for the
+equivalent option for agenda views."
   :type '(choice (const :tag "Don't loop" nil)
 		 (const :tag "All headlines in active region" t)
 		 (const :tag "In active region, headlines at the same level than the first one" start-level)