Document Credential: isConditionalMediationAvailable() static method (#41022)

* Document Credential: isConditionalMediationAvailable() static method

* Apply suggestions from code review

Co-authored-by: sideshowbarker <mike@w3.org>

---------

Co-authored-by: sideshowbarker <mike@w3.org>

Author: Elchi3

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

@@ -24,9 +24,10 @@ The **`Credential`** interface of the [Credential Management API](/en-US/docs/We
 - {{domxref("Credential.type")}} {{ReadOnlyInline}}
   - : Returns a string containing the credential's type. Valid values are `password`, `federated`, `public-key`, `identity` and `otp`. (For {{domxref("PasswordCredential")}}, {{domxref("FederatedCredential")}}, {{domxref("PublicKeyCredential")}}, {{domxref("IdentityCredential")}} and {{domxref("OTPCredential")}})
 
-## Instance methods
+## Static methods
 
-None.
+- {{domxref("Credential.isConditionalMediationAvailable_static", "Credential.isConditionalMediationAvailable()")}}
+  - : Returns a {{jsxref("Promise")}} which always resolves to `false`. Subclasses may override this value.
 
 ## Examples
 

files/en-us/web/api/credential/isconditionalmediationavailable_static/index.md

@@ -0,0 +1,41 @@
+---
+title: "Credential: isConditionalMediationAvailable() static method"
+short-title: isConditionalMediationAvailable()
+slug: Web/API/Credential/isConditionalMediationAvailable_static
+page-type: web-api-static-method
+browser-compat: api.Credential.isConditionalMediationAvailable_static
+---
+
+{{APIRef("Web Authentication API")}}{{securecontext_header}}
+
+The **`isConditionalMediationAvailable()`** static method of the {{domxref("Credential")}} interface returns a {{jsxref("Promise")}} which resolves to `false`.
+
+Subclasses of {{domxref("Credential")}} override this method if they support conditional mediation. See {{domxref("PublicKeyCredential.isConditionalMediationAvailable_static", "PublicKeyCredential.isConditionalMediationAvailable()")}}, for example.
+
+## Syntax
+
+```js-nolint
+Credential.isConditionalMediationAvailable()
+```
+
+### Parameters
+
+None.
+
+### Return value
+
+A {{jsxref("Promise")}} which resolves to `false`.
+
+## Examples
+
+```js
+await Credential.isConditionalMediationAvailable(); // false
+```
+
+## Specifications
+
+{{Specifications}}
+
+## Browser compatibility
+
+{{Compat}}