Update custom components API to have @alpha stability.

packages/element-web-module-api/src/api/custom-components.ts

@@ -48,7 +48,7 @@ export type CustomMessageRenderHints = {
 
 /**
  * Function used to render a message component.
- * @alpha Unlikely to change
+ * @alpha Subject to change.
  */
 export type CustomMessageRenderFunction = (
     /**
@@ -63,7 +63,7 @@ export type CustomMessageRenderFunction = (
 
 /**
  * API for inserting custom components into Element.
- * @public
+ * @alpha Subject to change.
  */
 export interface CustomComponentsApi {
     /**

packages/element-web-module-api/src/api/index.ts

@@ -90,7 +90,7 @@ export interface Api extends LegacyModuleApiExtension, LegacyCustomisationsApiEx
 
     /**
      * The custom message component API.
-     * @public
+     * @alpha
      */
     readonly customComponents: CustomComponentsApi;
     /**