Fixes cursor hidden when marking text (#317)

* Fixes cursor hidden when marking text

* Fixes SwiftLint errors

Author: simonbs

Sources/Runestone/Library/UITextSelectionDisplayInteraction+Helpers.swift

@@ -0,0 +1,8 @@
+import UIKit
+
+@available(iOS 17, *)
+extension UITextSelectionDisplayInteraction {
+    func sbs_enableCursorBlinks() {
+        setValue(true, forKey: "rosruc".reversed() + "Blinks")
+    }
+}

Sources/Runestone/TextView/Core/TextView.swift

@@ -1394,6 +1394,10 @@ extension TextView: TextInputViewDelegate {
             if !view.viewHierarchyContainsCaret && self.editableTextInteraction.view != nil {
                 view.removeInteraction(self.editableTextInteraction)
                 view.addInteraction(self.editableTextInteraction)
+                if #available(iOS 17, *) {
+                    self.textInputView.sbs_textSelectionDisplayInteraction?.isActivated = true
+                    self.textInputView.sbs_textSelectionDisplayInteraction?.sbs_enableCursorBlinks()
+                }
             }
         }
     }