docs: Document display_url.

* Add contributor

* Document the display_url setting

* Fix typo in pattern example

* Locate Display URL doc section appropriately

website/site/content/docs/configuration-options.md

@@ -68,6 +68,16 @@ public_folder: "/images/uploads"
 
 Based on the settings above, if a user used an image widget field called `avatar` to upload and select an image called `philosoraptor.png`, the image would be saved to the repository at `/static/images/uploads/philosoraptor.png`, and the `avatar` field for the file would be set to `/images/uploads/philosoraptor.png`.
 
+## Display URL
+
+When the `display_url` setting is specified, the CMS UI will include a link in the fixed area at the top of the page, allowing content authors to easily return to your main site. The text of the link consists of the URL less the protocol portion (e.g., `your-site.com`).
+
+**Example:**
+
+```yaml
+display_url: https://your-site.com
+```
+
 ## Slug Type
 
 The `slug` option allows you to change how filenames for entries are created and sanitized. For modifying the actual data in a slug, see the per-collection option below.
@@ -174,7 +184,7 @@ fields:
   - label: "Title"
     name: "title"
     widget: "string"
-    pattern: ['.{10,}', "Must have at least 20 characters"]
+    pattern: ['.{20,}', "Must have at least 20 characters"]
   - {label: "Layout", name: "layout", widget: "hidden", default: "blog"}
   - {label: "Featured Image", name: "thumbnail", widget: "image", required: false}
   - {label: "Body", name: "body", widget: "markdown"}