docs: improve docs for default client authentication

Refs #761

Author: panva

docs/classes/Configuration.md

@@ -59,8 +59,8 @@ let config = new client.Configuration(server, clientId, clientSecret)
 | ------ | ------ | ------ |
 | `server` | [`ServerMetadata`](../interfaces/ServerMetadata.md) | Authorization Server Metadata |
 | `clientId` | `string` | Client Identifier at the Authorization Server |
-| `metadata`? | `string` \| [`Partial`](https://www.typescriptlang.org/docs/handbook/utility-types.html#partialtype)\<[`ClientMetadata`](../interfaces/ClientMetadata.md)\> | Client Metadata, when a string is passed in it is a shorthand for passing just [ClientMetadata.client\_secret](../interfaces/ClientMetadata.md#client_secret). |
-| `clientAuthentication`? | [`ClientAuth`](../type-aliases/ClientAuth.md) | Implementation of the Client's Authentication Method at the Authorization Server. |
+| `metadata`? | `string` \| [`Partial`](https://www.typescriptlang.org/docs/handbook/utility-types.html#partialtype)\<[`ClientMetadata`](../interfaces/ClientMetadata.md)\> | Client Metadata, when a string is passed it is a shorthand for passing just [ClientMetadata.client\_secret](../interfaces/ClientMetadata.md#client_secret). |
+| `clientAuthentication`? | [`ClientAuth`](../type-aliases/ClientAuth.md) | Implementation of the Client's Authentication Method at the Authorization Server. Default is [ClientSecretPost](../functions/ClientSecretPost.md) using the [ClientMetadata.client\_secret](../interfaces/ClientMetadata.md#client_secret). |
 
 #### Returns
 

docs/functions/discovery.md

@@ -31,8 +31,8 @@ NOT RECOMMENDED as it disables the [ServerMetadata.issuer](../interfaces/ServerM
 | ------ | ------ | ------ |
 | `server` | [`URL`](https://developer.mozilla.org/docs/Web/API/URL) | URL representation of the Authorization Server's Issuer Identifier |
 | `clientId` | `string` | Client Identifier at the Authorization Server |
-| `metadata`? | `string` \| [`Partial`](https://www.typescriptlang.org/docs/handbook/utility-types.html#partialtype)\<[`ClientMetadata`](../interfaces/ClientMetadata.md)\> | Client Metadata, when a string is passed in it is a shorthand for passing just [ClientMetadata.client\_secret](../interfaces/ClientMetadata.md#client_secret) |
-| `clientAuthentication`? | [`ClientAuth`](../type-aliases/ClientAuth.md) | - |
+| `metadata`? | `string` \| [`Partial`](https://www.typescriptlang.org/docs/handbook/utility-types.html#partialtype)\<[`ClientMetadata`](../interfaces/ClientMetadata.md)\> | Client Metadata, when a string is passed it is a shorthand for passing just [ClientMetadata.client\_secret](../interfaces/ClientMetadata.md#client_secret) |
+| `clientAuthentication`? | [`ClientAuth`](../type-aliases/ClientAuth.md) | Implementation of the Client's Authentication Method at the Authorization Server. Default is [ClientSecretPost](ClientSecretPost.md) using the [ClientMetadata.client\_secret](../interfaces/ClientMetadata.md#client_secret). |
 | `options`? | [`DiscoveryRequestOptions`](../interfaces/DiscoveryRequestOptions.md) |  |
 
 ## Returns

src/index.ts

@@ -1067,8 +1067,11 @@ function handleB2Clogin(server: URL, options?: DiscoveryRequestOptions) {
  * @param server URL representation of the Authorization Server's Issuer
  *   Identifier
  * @param clientId Client Identifier at the Authorization Server
- * @param metadata Client Metadata, when a string is passed in it is a shorthand
+ * @param metadata Client Metadata, when a string is passed it is a shorthand
  *   for passing just {@link ClientMetadata.client_secret}
+ * @param clientAuthentication Implementation of the Client's Authentication
+ *   Method at the Authorization Server. Default is {@link ClientSecretPost}
+ *   using the {@link ClientMetadata.client_secret}.
  * @param options
  *
  * @group OpenID Connect 1.0
@@ -1627,10 +1630,11 @@ export class Configuration
   /**
    * @param server Authorization Server Metadata
    * @param clientId Client Identifier at the Authorization Server
-   * @param metadata Client Metadata, when a string is passed in it is a
-   *   shorthand for passing just {@link ClientMetadata.client_secret}.
+   * @param metadata Client Metadata, when a string is passed it is a shorthand
+   *   for passing just {@link ClientMetadata.client_secret}.
    * @param clientAuthentication Implementation of the Client's Authentication
-   *   Method at the Authorization Server.
+   *   Method at the Authorization Server. Default is {@link ClientSecretPost}
+   *   using the {@link ClientMetadata.client_secret}.
    */
   constructor(
     server: ServerMetadata,