Document fern logout command (CLI Reference) (#761)

Author: devalog

fern/products/cli-api-reference/pages/commands.mdx

@@ -10,6 +10,8 @@ hideOnThisPage: true
 | [`fern init`](#fern-init) | Create new Fern project from OpenAPI spec or scratch |
 | [`fern check`](#fern-check) | Validate API definition & configuration |
 | [`fern upgrade`](#fern-upgrade) | Update Fern CLI & generators to latest versions |
+| [`fern login`](#fern-login) | Login to Fern CLI via GitHub or Google |
+| [`fern logout`](#fern-logout) | Log out of the Fern CLI |
 
 ## Documentation Commands
 
@@ -318,7 +320,7 @@ hideOnThisPage: true
 
   <Accordion title="fern login">
 
-    Use `fern login` to login to the Fern CLI via GitHub. Logging in allows you 
+    Use `fern login` to login to the Fern CLI via GitHub or Google. Logging in allows you 
     join GitHub organizations, gain permissions, and contribute to projects.
 
     <CodeBlock title="terminal">
@@ -341,6 +343,21 @@ hideOnThisPage: true
 
   </Accordion>
 
+  <Accordion title="fern logout">
+
+    Use `fern logout` to log out of the Fern CLI. This will clear your authentication 
+    credentials and revoke access to your GitHub organizations and permissions.
+
+    <CodeBlock title="terminal">
+    ```bash
+    fern logout
+    ```
+    </CodeBlock>
+
+    After logging out, you'll need to run [`fern login`](#fern-login) again to access protected features.
+
+  </Accordion>
+
   <Accordion title="fern token">
 
     Use `fern token `to generate a `FERN_TOKEN` specific to your organization defined