Improve VoiceOver labels for notifications

Closes #350

Tusker/Screens/Notifications/NotificationsTableViewController.swift

@@ -296,6 +296,7 @@ class NotificationsTableViewController: DiffableTimelineLikeTableViewController<
                 completion(true)
             }
         }
+        dismissAction.accessibilityLabel = "Dismiss Notification"
         dismissAction.image = UIImage(systemName: "clear.fill")
         
         let cellConfiguration = (tableView.cellForRow(at: indexPath) as? TableViewSwipeActionProvider)?.trailingSwipeActionsConfiguration()

Tusker/Views/Notifications/ActionNotificationGroupTableViewCell.swift

@@ -222,6 +222,31 @@ class ActionNotificationGroupTableViewCell: UITableViewCell {
         updateTimestampWorkItem = nil
     }
     
+    // MARK: Accessibility
+    
+    override var accessibilityLabel: String? {
+        get {
+            let first = group.notifications.first!
+            var str = ""
+            switch group.kind {
+            case .favourite:
+                str += "Favorited by "
+            case .reblog:
+                str += "Reblogged by "
+            default:
+                return nil
+            }
+            str += first.account.displayNameWithoutCustomEmoji
+            if group.notifications.count > 1 {
+                str += " and \(group.notifications.count - 1) more"
+            }
+            str += ", \(first.createdAt.formatted(.relative(presentation: .numeric))), "
+            str += statusContentLabel.text ?? ""
+            return str
+        }
+        set {}
+    }
+
 }
 
 extension ActionNotificationGroupTableViewCell: SelectableTableViewCell {

Tusker/Views/Notifications/FollowNotificationGroupTableViewCell.swift

@@ -186,6 +186,22 @@ class FollowNotificationGroupTableViewCell: UITableViewCell {
         updateTimestampWorkItem = nil
     }
     
+    // MARK: Accessibility
+    
+    override var accessibilityLabel: String? {
+        get {
+            let first = group.notifications.first!
+            var str = "Followed by "
+            str += first.account.displayNameWithoutCustomEmoji
+            if group.notifications.count > 1 {
+                str += " and \(group.notifications.count - 1) more"
+            }
+            str += ", \(first.createdAt.formatted(.relative(presentation: .numeric)))"
+            return str
+        }
+        set {}
+    }
+
 }
 
 extension FollowNotificationGroupTableViewCell: SelectableTableViewCell {

Tusker/Views/Notifications/FollowRequestNotificationTableViewCell.swift

@@ -135,6 +135,29 @@ class FollowRequestNotificationTableViewCell: UITableViewCell {
         self.stackView.addArrangedSubview(label)
     }
     
+    // MARK: Accessibility
+    
+    override var accessibilityLabel: String? {
+        get {
+            guard let notification else { return nil }
+            var str = "Follow requested by "
+            str += notification.account.displayNameWithoutCustomEmoji
+            str += ", \(notification.createdAt.formatted(.relative(presentation: .numeric)))"
+            return str
+        }
+        set {}
+    }
+    
+    override var accessibilityCustomActions: [UIAccessibilityCustomAction]? {
+        get {
+            return [
+                UIAccessibilityCustomAction(name: "Accept Request", target: self, selector: #selector(acceptButtonPressed)),
+                UIAccessibilityCustomAction(name: "Reject Request", target: self, selector: #selector(acceptButtonPressed)),
+            ]
+        }
+        set {}
+    }
+    
     // MARK: - Interaction
     
     @IBAction func rejectButtonPressed() {

Tusker/Views/Notifications/PollFinishedTableViewCell.swift

@@ -93,6 +93,25 @@ class PollFinishedTableViewCell: UITableViewCell {
         updateTimestampWorkItem = nil
     }
     
+    // MARK: Accessibility
+    
+    override var accessibilityLabel: String? {
+        get {
+            guard let notification else { return nil }
+            var str = "Poll from "
+            str += notification.account.displayNameWithoutCustomEmoji
+            str += " finished "
+            str += notification.createdAt.formatted(.relative(presentation: .numeric))
+            if let poll = notification.status?.poll,
+               poll.options.contains(where: { ($0.votesCount ?? 0) > 0 }) {
+                let winner = poll.options.max(by: { ($0.votesCount ?? 0) < ($1.votesCount ?? 0) })!
+                str += ", winning option: \(winner.title)"
+            }
+            return str
+        }
+        set {}
+    }
+    
 }
 
 extension PollFinishedTableViewCell: SelectableTableViewCell {

Tusker/Views/Notifications/StatusUpdatedNotificationTableViewCell.swift

@@ -85,6 +85,22 @@ class StatusUpdatedNotificationTableViewCell: UITableViewCell {
         updateTimestampWorkItem = nil
     }
     
+    // MARK: Accessibility
+    
+    override var accessibilityLabel: String? {
+        get {
+            guard let notification else { return nil }
+            var str = "Post from "
+            str += notification.account.displayNameWithoutCustomEmoji
+            str += " edited "
+            str += notification.createdAt.formatted(.relative(presentation: .numeric))
+            str += ", "
+            str += contentLabel.text ?? ""
+            return str
+        }
+        set {}
+    }
+    
 }
 
 extension StatusUpdatedNotificationTableViewCell: SelectableTableViewCell {