Add Coccinelle rule to use NameStr

Direct access of the `.data` member of `NameData` structures are
discuraged and `NameStr` should be used instead.

Also adding one instance that was missed in #5336.

coccinelle/namestr.cocci

@@ -0,0 +1,25 @@
+// Find direct access of data member of a NameData structure
+//
+// These should use NameStr instead.
+
+@@
+typedef NameData;
+typedef Name;
+NameData E;
+@@
+- E.data
++ NameStr(E)
+
+@@
+NameData *E;
+@@
+- E->data
++ NameStr(*E)
+
+@@
+Name E;
+@@
+- E->data
++ NameStr(*E)
+
+

tsl/src/deparse.c

@@ -151,7 +151,7 @@ column_is_serial(Relation rel, Name column)
 											   NameStr(rel->rd_rel->relname));
 	InitFunctionCallInfoData(*fcinfo, NULL, 2, InvalidOid, NULL, NULL);
 	FC_ARG(fcinfo, 0) = CStringGetTextDatum(relation_name);
-	FC_ARG(fcinfo, 1) = CStringGetTextDatum(column->data);
+	FC_ARG(fcinfo, 1) = CStringGetTextDatum(NameStr(*column));
 	FC_NULL(fcinfo, 0) = false;
 	FC_NULL(fcinfo, 1) = false;
 	pg_get_serial_sequence(fcinfo);