Add jsdoc comments for user verification, password reprompt, and appApiAction (#754)

* Rename and add comments to clarify password reprompt classes

* Add comment for appApiAction

angular/src/directives/api-action.directive.ts

@@ -5,6 +5,12 @@ import { ErrorResponse } from "jslib-common/models/response/errorResponse";
 
 import { ValidationService } from "../services/validation.service";
 
+/**
+ * Provides error handling, in particular for any error returned by the server in an api call.
+ * Attach it to a <form> element and provide the name of the class property that will hold the api call promise.
+ * e.g. <form [appApiAction]="this.formPromise">
+ * Any errors/rejections that occur will be intercepted and displayed as error toasts.
+ */
 @Directive({
   selector: "[appApiAction]",
 })