Fix "TSDoc: TSDoc Playground" double title

_layouts/default.html

@@ -6,7 +6,9 @@
 
     {{ page.head_content }}
 
-    {% if page.title %}
+    {% if page.full_title %}
+    <title>{{ page.full_title }}</title>
+    {% elsif page.title %}
     <title>TSDoc: {{ page.title }}</title>
     {% else %}
     <title>TSDoc</title>

permalinks/play.html

@@ -1,6 +1,6 @@
 ---
 layout: default
-title: TSDoc Playground
+full_title: TSDoc Playground
 permalink: /play.html
 head_content: |-
   <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">