Add missing outfuncs.c support for struct InhRelation.

This is needed to support debug_print_parse, per report from Jon Nelson.
Cursory testing via the regression tests suggests we aren't missing
anything else.

src/backend/nodes/outfuncs.c

@@ -1375,6 +1375,15 @@ _outDefElem(StringInfo str, DefElem *node)
 	WRITE_NODE_FIELD(arg);
 }
 
+static void
+_outInhRelation(StringInfo str, InhRelation *node)
+{
+	WRITE_NODE_TYPE("INHRELATION");
+
+	WRITE_NODE_FIELD(relation);
+	WRITE_BOOL_FIELD(including_defaults);
+}
+
 static void
 _outLockingClause(StringInfo str, LockingClause *node)
 {
@@ -2099,6 +2108,9 @@ _outNode(StringInfo str, void *obj)
 			case T_DefElem:
 				_outDefElem(str, obj);
 				break;
+			case T_InhRelation:
+				_outInhRelation(str, obj);
+				break;
 			case T_LockingClause:
 				_outLockingClause(str, obj);
 				break;