fix(examples) join usage (#2425)

Use 'join' correctly on Python scripts

examples/widgets/dropdown/lv_example_dropdown_1.py

@@ -10,16 +10,16 @@ def event_handler(e):
 # Create a normal drop down list
 dd = lv.dropdown(lv.scr_act())
 dd.set_options("\n".join([
-    "Apple\n"
-    "Banana\n"
-    "Orange\n"
-    "Cherry\n"
-    "Grape\n"
-    "Raspberry\n"
-    "Melon\n"
-    "Orange\n"
-    "Lemon\n"
-    "Nuts\n"]))
+    "Apple",
+    "Banana",
+    "Orange",
+    "Cherry",
+    "Grape",
+    "Raspberry",
+    "Melon",
+    "Orange",
+    "Lemon",
+    "Nuts"]))
 
 dd.align(lv.ALIGN.TOP_MID, 0, 20)
 dd.add_event_cb(event_handler, lv.EVENT.ALL, None)

examples/widgets/dropdown/lv_example_dropdown_2.py

@@ -3,11 +3,11 @@
 #
 
 opts = "\n".join([
-    "Apple\n"
-    "Banana\n"
-    "Orange\n"
-    "Melon\n"
-    "Grape\n"
+    "Apple",
+    "Banana",
+    "Orange",
+    "Melon",
+    "Grape",
     "Raspberry"])
 
 dd = lv.dropdown(lv.scr_act())

examples/widgets/dropdown/lv_example_dropdown_3.py

@@ -30,12 +30,12 @@ def event_cb(e):
 # Create a drop down list
 dropdown = lv.dropdown(lv.scr_act())
 dropdown.align(lv.ALIGN.TOP_LEFT, 10, 10)
-dropdown.set_options("".join([
-    "New project\n",
-    "New file\n",
-    "Open project\n",
-    "Recent projects\n",
-    "Preferences\n",
+dropdown.set_options("\n".join([
+    "New project",
+    "New file",
+    "Open project",
+    "Recent projects",
+    "Preferences",
     "Exit"]))
 
 # Set a fixed text to display on the button of the drop-down list