Made changes asked in review by HonzaKral

Add documentation for new command in django-admin.

docs/ref/django-admin.txt

@@ -863,6 +863,16 @@ Note that the order in which the SQL files are processed is undefined.
 The :djadminopt:`--database` option can be used to specify the database for
 which to print the SQL.
 
+sqldropindexes <appname appname ...>
+--------------------------------
+
+.. django-admin:: sqldropindexes
+
+Prints the DROP INDEX SQL statements for the given app name(s).
+
+The :djadminopt:`--database` option can be used to specify the database for
+which to print the SQL.
+
 sqlflush
 --------