Notifications: Review of PR to include path path #4629

- Merged book and chapter name items to a single page path list item
  which has links to parent page/chapter.
- Added permission filtering to page path elements.
- Added page path to also be on comment notifications.
- Updated testing to cover.
- Added new Message Line objects to support.

Done during review of #4629

app/Activity/Notifications/MessageParts/EntityLinkMessageLine.php

@@ -0,0 +1,29 @@
+<?php
+
+namespace BookStack\Activity\Notifications\MessageParts;
+
+use BookStack\Entities\Models\Entity;
+use Illuminate\Contracts\Support\Htmlable;
+use Stringable;
+
+/**
+ * A link to a specific entity in the system, with the text showing its name.
+ */
+class EntityLinkMessageLine implements Htmlable, Stringable
+{
+    public function __construct(
+        protected Entity $entity,
+        protected int $nameLength = 120,
+    ) {
+    }
+
+    public function toHtml(): string
+    {
+        return '<a href="' . e($this->entity->getUrl()) . '">' . e($this->entity->getShortName($this->nameLength)) . '</a>';
+    }
+
+    public function __toString(): string
+    {
+        return "{$this->entity->getShortName($this->nameLength)} ({$this->entity->getUrl()})";
+    }
+}