Add shortcutDetails to drive file fields (#1413)

src/GamCommands.txt

@@ -353,6 +353,7 @@ If an item contains spaces, it should be surrounded by ".
 	shared|
 	sharedwithmedate|sharedwithmetime|
 	sharinguser|
+	shortcutdetails|
 	size|
 	spaces|
 	starred|

src/gam/var.py

@@ -500,6 +500,7 @@ DRIVEFILE_FIELDS_CHOICES_MAP = {
     'sharedwithmedate': 'sharedWithMeDate',
     'sharedwithmetime': 'sharedWithMeDate',
     'sharinguser': 'sharingUser',
+    'shortcutdetails': 'shortcutDetails',
     'spaces': 'spaces',
     'thumbnaillink': 'thumbnailLink',
     'title': 'title',