Style: Trim trailing whitespace and ensure newline at EOF

Found by apply the file_format checks again via #91597.

modules/gdscript/tests/scripts/completion/get_node/local_scene/class_local_scene.cfg

@@ -6,7 +6,7 @@ include=[
     {"display": "add_child"},
     {"display": "owner"},
     {"display": "child_entered_tree"},
-    
+
     ; GDScript: class_a.notest.gd
     {"display": "property_of_a"},
     {"display": "func_of_a"},

modules/gdscript/tests/scripts/completion/get_node/local_scene/native_local_scene.cfg

@@ -6,7 +6,7 @@ include=[
     {"display": "add_child"},
     {"display": "owner"},
     {"display": "child_entered_tree"},
-    
+
     ; AnimationPlayer
     {"display": "autoplay"},
     {"display": "play"},