Fix indentation on mouse_and_input_coordinates.rst

There was a space missing, causing inconsistent indentation and making the code not copy pastable.

tutorials/inputs/mouse_and_input_coordinates.rst

@@ -29,14 +29,14 @@ for example:
  .. code-tab:: gdscript GDScript
 
     func _input(event):
-       # Mouse in viewport coordinates.
-       if event is InputEventMouseButton:
-           print("Mouse Click/Unclick at: ", event.position)
-       elif event is InputEventMouseMotion:
-           print("Mouse Motion at: ", event.position)
-
-       # Print the size of the viewport.
-       print("Viewport Resolution is: ", get_viewport().get_visible_rect().size)
+        # Mouse in viewport coordinates.
+        if event is InputEventMouseButton:
+            print("Mouse Click/Unclick at: ", event.position)
+        elif event is InputEventMouseMotion:
+            print("Mouse Motion at: ", event.position)
+
+        # Print the size of the viewport.
+        print("Viewport Resolution is: ", get_viewport().get_visible_rect().size)
 
  .. code-tab:: csharp