fix(args): add case-insensitive note to --ignore-pattern HELP_TEXT

Author: markuslf

args.py

@@ -60,6 +60,7 @@
     ),
     '--ignore-pattern': (
         'Any item containing this pattern will be ignored. '
+        'Case-insensitive. '
         'Can be specified multiple times. '
         'Example: `boot` matches both `/boot` and `/boot/efi`.'
     ),