docs: improved SEO of documentation (#3117)

* docs: added description to documentation pages

* docs: added more descriptions

* docs: finished improving meta description

* docs: added searchbox structured data

* docs: added breadcrumbs structured data

* docs: added how to structured data

* docs: improved 404 page

* docs: added how-to frontmatter option

docs/content/user-guide/sales-channels/index.md

@@ -1,17 +1,12 @@
 ---
 sidebar_position: 1
+description: 'Medusa admin allows merchants to manage their sales channels. Merchants can separate products into multiple sales channels.'
 ---
 
 # Sales Channels Overview
 
 In this document, you’ll get an overview of sales channels in Medusa and learn about their importance in your ecommerce store.
 
-:::note
-
-Sales Channels are currently in beta mode and need to be [manually enabled in your store using feature flags](../../advanced/backend/feature-flags/toggle.md). If you’re unsure how that works, please contact your technical team.
-
-:::
-
 ## Overview
 
 Sales Channels are multiple channels that you can sell your products through. For example, you can have a sales channel for the web storefront, another for the mobile app, and another for selling across social media platforms.

docs/content/user-guide/sales-channels/manage.mdx

@@ -1,5 +1,7 @@
 ---
 sidebar_position: 2
+description: 'This user guide explains how to manage sales channels on the Medusa admin. Learn how to create, edit, and delete sales channels.'
+addHowToData: true
 ---
 
 import UiIcon from '@site/src/components/UiIcon';

docs/content/user-guide/sales-channels/products.mdx

@@ -1,6 +1,8 @@
 ---
 sidebar_position: 3
 sidebar_label: Manage Products
+description: 'This user guide explains how to manage products in sales channels on the Medusa admin.'
+addHowToData: true
 ---
 
 import UiIcon from '@site/src/components/UiIcon';