web/api/web_authentication_api: add missing closing tag (mdn#38013)

* web/api/web_authentication_api: add missing closing tag

* Update index.md

* Update files/en-us/web/api/web_authentication_api/index.md

* Update index.md

---------

Co-authored-by: Joshua Chen <[email protected]>

Author: islishude

files/en-us/web/api/web_authentication_api/index.md

@@ -170,8 +170,8 @@ The code below shows how you might use `getClientCapabilities()` to check if the
 Note that the actual actions performed depend on your site.
 For sites that _require_ biometric authentication, you might replace the login UI with a message indicating that biometric authentication is needed, and the user should try a different browser or device.
 
-````js
-async function checkisUserVerifyingPlatformAuthenticatorAvailable() {
+```js
+async function checkIsUserVerifyingPlatformAuthenticatorAvailable() {
   const capabilities = await PublicKeyCredential.getClientCapabilities();
   // Check the capability: userVerifyingPlatformAuthenticator
   if (capabilities.userVerifyingPlatformAuthenticator) {
@@ -180,6 +180,7 @@ async function checkisUserVerifyingPlatformAuthenticatorAvailable() {
     // Perform actions if biometric support is not available.
   }
 }
+```
 
 ## Controlling access to the API
 
@@ -203,7 +204,7 @@ If you wish to allow access to a specific subdomain only, you could provide it l
 ```http
 Permissions-Policy: publickey-credentials-get=("https://subdomain.example.com")
 Permissions-Policy: publickey-credentials-create=("https://subdomain.example.com")
-````
+```
 
 ### Allowing embedded `create` and `get()` calls in an `<iframe>`