Fix superfluous `"` in error message

(cherry picked from commit fa8fec2cc1d5773693b50a5c4fbbf97e28fd15b1)

modules/gdscript/gdscript_parser.cpp

@@ -2444,7 +2444,7 @@ GDScriptParser::ExpressionNode *GDScriptParser::parse_binary_operator(Expression
 	complete_extents(operation);
 
 	if (operation->right_operand == nullptr) {
-		push_error(vformat(R"(Expected expression after "%s" operator.")", op.get_name()));
+		push_error(vformat(R"(Expected expression after "%s" operator.)", op.get_name()));
 	}
 
 	// TODO: Also for unary, ternary, and assignment.