Mention-only notifications (or notification filters)

[xnuk]

Currently Pinafore requesting this query params for finding mentions (I put some spaces for readability):

GET /api/v1/notifications
  ? limit=20
  & exclude_types[]=follow
  & exclude_types[]=favourite
  & exclude_types[]=reblog
  & exclude_types[]=poll
  & exclude_types[]=admin.sign_up
  & exclude_types[]=update
  & exclude_types[]=follow_request
  & exclude_types[]=admin.report

Currently SkyBridge respond with: [{ "type": "favourite", ... }, { "type": "reblog", ... } ...]