Add test case for comma after lambda function argument

#161

Author: NathanLovato

tests/expected/function_argument_lambda_comma.gd

@@ -0,0 +1,11 @@
+func test():
+	hurt_tween.tween_method(
+		func(weight):
+			var hue = interpolate_hue(current_hue, target_hue, weight)
+			# The tailing comma here should stay there as it completes the
+			# lambda argument
+			starnest.set_instance_shader_parameter("hue_shift", hue),
+		0.0,
+		1.0,
+		2.0,
+	)

tests/input/function_argument_lambda_comma.gd

@@ -0,0 +1,11 @@
+func test():
+	hurt_tween.tween_method(
+		func(weight):
+			var hue = interpolate_hue(current_hue, target_hue, weight)
+			# The tailing comma here should stay there as it completes the
+			# lambda argument
+			starnest.set_instance_shader_parameter("hue_shift", hue),
+		0.0,
+		1.0,
+		2.0,
+	)