chore: add information about the new signOut redirect url option

src/pages/gen1/[platform]/build-a-backend/auth/add-social-provider/index.mdx

@@ -739,13 +739,81 @@ function App() {
 </Block>
 </BlockSwitcher>
 
+### Redirect URIs
+
+You can provide multiple _Sign in_ & _Sign out_ redirect URI(s).
+
+If you have multiple redirect URI inputs, you'll need to pass them in your Amplify configuration. For example:
+
+```javascript
+Amplify.configure({
+  Auth: {
+    Cognito: {
+      loginWith: {
+        oauth: {
+          redirectSignIn: [
+            'myDevApp://'
+          ],
+          redirectSignOut: [
+            'myDevApp://',
+            'myProdApp://'
+          ],
+          ...oauthConfig
+        }
+      },
+      ...userPoolConfig
+    }
+  }
+});
+```
+
+#### Specifying a redirect URI on sign out
+If you have multiple redirect urls configured, you may choose to override the default behavior of selecting a redirect url and provide the one of your choosing when calling `signOut`. The provided redirect url should match at least one of the configured redirect urls. If no redirect url is provided to `signOut`, the first item from the the configured redirect urls list that does not contain a http nor https prefix will be picked.
+
+```ts
+import { Amplify } from 'aws-amplify';
+import { signOut } from 'aws-amplify/auth';
+
+Amplify.configure({
+  Auth: {
+    Cognito: {
+      loginWith: {
+        oauth: {
+          redirectSignIn: [
+            'myDevApp://'
+          ],
+          redirectSignOut: [
+            'myDevApp://',
+            'https://oidcProvider/?logout_uri=myDevApp://'
+          ],
+          ...oauthConfig
+        }
+      },
+      ...userPoolConfig
+    }
+  }
+});
+
+function handleSignOut() {
+  signOut({
+    global: false,
+    oauth: {
+      redirectUrl: 'https://oidcProvider/?logout_uri=myDevApp://'
+    }
+  });
+}
+
+
+```
+<Callout> Irrespective of whether a `redirectUrl` is provided to `signOut`, a URL that does not contain http or https is expected to be present in the configured redirect URL list. This is because iOS requires an appScheme when creating the web session. </Callout>
+
 </InlineFilter>
 
 <InlineFilter filters={["javascript", "angular", "nextjs", "react", "vue"]}>
 
-### Redirect URLs
+### Redirect URIs
 
-For _Sign in Redirect URI(s)_ inputs, you can put one URI for local development and one for production. Example: `http://localhost:3000/` in dev and `https://www.example.com/` in production. The same is true for _Sign out redirect URI(s)_.
+For _Sign in Redirect URI(s)_ inputs, you can put one URI for local development and one for production. Example: `http://localhost:3000/` in dev and `https://www.example.com/` in production. The same is true for _Sign out Redirect URI(s)_.
 
 If you have multiple redirect URI inputs, you'll need to pass them in your Amplify configuration. For example:
 
@@ -943,6 +1011,43 @@ function App() {
 
 </Accordion>
 
+#### Specifying a redirect URI on sign out
+If you have multiple redirect urls configured, you may choose to override the default behavior of selecting a redirect url and provide the one of your choosing when calling `signOut`. The provided redirect url should match at least one of the configured redirect urls. If no redirect url is provided to `signOut`, one will be selected based on the current app domain.
+
+```ts
+import { Amplify } from 'aws-amplify';
+import { signOut } from 'aws-amplify/auth';
+
+Amplify.configure({
+  Auth: {
+    Cognito: {
+      loginWith: {
+        oauth: {
+          redirectSignIn: [
+            'http://localhost:3000/',
+            'https://www.example.com/'
+          ],
+          redirectSignOut: [
+            'http://localhost:3000/',
+            'https://www.example.com/'
+          ],
+          ...oauthConfig
+        }
+      },
+      ...userPoolConfig
+    }
+  }
+});
+
+signOut({
+  global: false,
+  oauth: {
+    redirectUrl: 'https://www.example.com/'
+  }
+});
+
+```
+
 ### (Required for Multi-Page Applications) Complete Social Sign In after Redirect
 
 If you are developing a multi-page application, and the redirected page is not the same page that initiated the sign in, you will need to add the following code to the redirected page to ensure the sign in gets completed: