style(examples) fix style issues in Python examples (#2880)

Removes all semicolons at line endings in the Python examples.

examples/widgets/checkbox/lv_example_checkbox_1.py

@@ -4,9 +4,9 @@ def event_handler(e):
     if code == lv.EVENT.VALUE_CHANGED:
         txt = obj.get_text()
         if obj.get_state() & lv.STATE.CHECKED:
-            state =  "Checked"
+            state = "Checked"
         else:
-            state = "Unchecked";
+            state = "Unchecked"
         print(txt + ":" + state)