Streamline banner component documentation (#1104)

* Update components/banner.mdx

* add to docs.json

* update frontmatter

* copy edit banners

* update description

---------

Co-authored-by: mintlify[bot] <109931778+mintlify[bot]@users.noreply.github.com>
Co-authored-by: Ethan Palm <[email protected]>

Author: mintlify[bot]

components/banner.mdx

@@ -0,0 +1,42 @@
+---
+title: "Banner"
+description: "Add a banner to display important site-wide announcements and notifications"
+icon: "layout-panel-top"
+---
+
+Use banners to display important announcements, updates, or notifications across your entire documentation site. Banners appear at the top of every page, support Markdown formatting, and can be made dismissible.
+
+To add a banner, use the `banner` property in your `docs.json`:
+
+<CodeGroup>
+  ```json Product announcements wrap
+  "banner": {
+    "content": "🚀 Version 2.0 is now live! See our [changelog](/changelog) for details.",
+    "dismissible": true 
+  }
+  ```
+
+  ```json Maintenance notices wrap
+  "banner": {
+    "content": "⚠️ Scheduled maintenance: API will be unavailable December 15, 2-4 AM UTC",
+    "dismissible": false
+  }
+  ```
+
+  ```json Required actions wrap
+  "banner": {
+    "content": "**Action required:** Migrate to our new version by January 1. [Migration guide](/migration)",
+    "dismissible": true
+  }
+  ```
+</CodeGroup>
+
+## Properties
+
+<ResponseField name="content" type="string" required>
+  The banner message. Supports plain text and Markdown formatting.
+</ResponseField>
+
+<ResponseField name="dismissible" type="boolean">
+  Whether users can dismiss the banner. When `true`, users can close the banner and it won't reappear for their session. Defaults to `false`.
+</ResponseField>

docs.json

@@ -87,7 +87,8 @@
               "components/steps",
               "components/tabs",
               "components/tooltips",
-              "components/update"
+              "components/update",
+              "components/banner"
             ]
           },
           {