Move function_with_argtypes to a better location

It was apparently added for use by GRANT/REVOKE, but move it closer to
where other function signature related things are kept.
Reviewed-by: Alvaro Herrera <alvherre@2ndquadrant.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>

src/backend/parser/gram.y

@@ -6533,22 +6533,6 @@ opt_grant_grant_option:
 			| /*EMPTY*/ { $$ = FALSE; }
 		;
 
-function_with_argtypes_list:
-			function_with_argtypes					{ $$ = list_make1($1); }
-			| function_with_argtypes_list ',' function_with_argtypes
-													{ $$ = lappend($1, $3); }
-		;
-
-function_with_argtypes:
-			func_name func_args
-				{
-					FuncWithArgs *n = makeNode(FuncWithArgs);
-					n->funcname = $1;
-					n->funcargs = extractArgTypes($2);
-					$$ = n;
-				}
-		;
-
 /*****************************************************************************
  *
  * GRANT and REVOKE ROLE statements
@@ -6901,6 +6885,22 @@ func_args_list:
 			| func_args_list ',' func_arg			{ $$ = lappend($1, $3); }
 		;
 
+function_with_argtypes_list:
+			function_with_argtypes					{ $$ = list_make1($1); }
+			| function_with_argtypes_list ',' function_with_argtypes
+													{ $$ = lappend($1, $3); }
+		;
+
+function_with_argtypes:
+			func_name func_args
+				{
+					FuncWithArgs *n = makeNode(FuncWithArgs);
+					n->funcname = $1;
+					n->funcargs = extractArgTypes($2);
+					$$ = n;
+				}
+		;
+
 /*
  * func_args_with_defaults is separate because we only want to accept
  * defaults in CREATE FUNCTION, not in ALTER etc.