content: Add note to practice in lesson 11 not to use local variables

Author: NathanLovato

course/lesson-11-time-delta/lesson.tres

@@ -267,7 +267,9 @@ practice_id = "res://course/lesson-11-time-delta/practice-x0c7DDiz.tres"
 title = "Moving in a Circle Using Delta"
 goal = "In this practice, make the robot move in a smooth circle using delta.
 
-To get this movement, the robot should rotate [code]2[/code] radians per second and move [code]100[/code] pixels per second towards clockwise."
+To get this movement, the robot should rotate [code]2[/code] radians per second and move [code]100[/code] pixels per second towards clockwise.
+
+[b]Note:[/b] Please write the values in the parentheses when calling the functions. If you define extra variables, we will not be able to check your practice."
 starting_code = "func _process(delta):
 	"
 cursor_line = 0