Move related functions next to each other in pg_publication.c.

This also improves comments atop is_publishable_class().

Author: Peter Smith
Reviewed-by: Amit Kapila, Hou Zhijie
Discussion: https://postgr.es/m/CAHut+PupQ5UW9A9ut0Yjt21J9tHhx958z5L0k8-9hTYf_NYqxA@mail.gmail.com

Author: Amit Kapila

src/backend/catalog/pg_publication.c

@@ -115,8 +115,8 @@ check_publication_add_schema(Oid schemaid)
  * Returns if relation represented by oid and Form_pg_class entry
  * is publishable.
  *
- * Does same checks as the above, but does not need relation to be opened
- * and also does not throw errors.
+ * Does same checks as check_publication_add_relation() above, but does not
+ * need relation to be opened and also does not throw errors.
  *
  * XXX  This also excludes all tables with relid < FirstNormalObjectId,
  * ie all tables created during initdb.  This mainly affects the preinstalled
@@ -140,6 +140,15 @@ is_publishable_class(Oid relid, Form_pg_class reltuple)
 		relid >= FirstNormalObjectId;
 }
 
+/*
+ * Another variant of is_publishable_class(), taking a Relation.
+ */
+bool
+is_publishable_relation(Relation rel)
+{
+	return is_publishable_class(RelationGetRelid(rel), rel->rd_rel);
+}
+
 /*
  * Filter out the partitions whose parent tables were also specified in
  * the publication.
@@ -179,15 +188,6 @@ filter_partitions(List *relids)
 	return result;
 }
 
-/*
- * Another variant of this, taking a Relation.
- */
-bool
-is_publishable_relation(Relation rel)
-{
-	return is_publishable_class(RelationGetRelid(rel), rel->rd_rel);
-}
-
 /*
  * Returns true if any schema is associated with the publication, false if no
  * schema is associated with the publication.