chore: add revocation endpoint to oauth well-known (#20561)

Was added to apps endpoints, but not the wider site ones. This is a site
wide oauth route

coderd/apidoc/docs.go

@@ -15435,6 +15435,9 @@ const docTemplate = `{
                         "type": "string"
                     }
                 },
+                "revocation_endpoint": {
+                    "type": "string"
+                },
                 "scopes_supported": {
                     "type": "array",
                     "items": {

coderd/apidoc/swagger.json

@@ -13989,6 +13989,9 @@
 						"type": "string"
 					}
 				},
+				"revocation_endpoint": {
+					"type": "string"
+				},
 				"scopes_supported": {
 					"type": "array",
 					"items": {

coderd/oauth2provider/metadata.go

@@ -18,6 +18,7 @@ func GetAuthorizationServerMetadata(accessURL *url.URL) http.HandlerFunc {
 			AuthorizationEndpoint:             accessURL.JoinPath("/oauth2/authorize").String(),
 			TokenEndpoint:                     accessURL.JoinPath("/oauth2/tokens").String(),
 			RegistrationEndpoint:              accessURL.JoinPath("/oauth2/register").String(), // RFC 7591
+			RevocationEndpoint:                accessURL.JoinPath("/oauth2/revoke").String(),   // RFC 7009
 			ResponseTypesSupported:            []string{"code"},
 			GrantTypesSupported:               []string{"authorization_code", "refresh_token"},
 			CodeChallengeMethodsSupported:     []string{"S256"},