Improve wp user remove-role docs and output when no role argument given

Co-authored-by: swissspidy <841956+swissspidy@users.noreply.github.com>

Author: Copilot

features/user.feature

@@ -352,7 +352,10 @@ Feature: Manage WordPress users
       | roles | author |
 
     When I run `wp user remove-role 1`
-    Then STDOUT should not be empty
+    Then STDOUT should be:
+      """
+      Success: Removed all roles from admin (1).
+      """
 
     When I run `wp user get 1`
     Then STDOUT should be a table containing rows:

src/User_Command.php

@@ -807,7 +807,8 @@ public function add_role( $args, $assoc_args ) {
 	 * : User ID, user email, or user login.
 	 *
 	 * [<role>...]
-	 * : Remove the specified role(s) from the user.
+	 * : Remove the specified role(s) from the user. If not passed, all roles are
+	 * removed from the user.
 	 *
 	 * ## EXAMPLES
 	 *
@@ -817,6 +818,9 @@ public function add_role( $args, $assoc_args ) {
 	 *     $ wp user remove-role 12 author editor
 	 *     Success: Removed 'author', 'editor' roles for johndoe (12).
 	 *
+	 *     $ wp user remove-role 12
+	 *     Success: Removed all roles from johndoe (12).
+	 *
 	 * @subcommand remove-role
 	 */
 	public function remove_role( $args, $assoc_args ) {
@@ -844,7 +848,7 @@ public function remove_role( $args, $assoc_args ) {
 				$user->remove_all_caps();
 			}
 
-			WP_CLI::success( "Removed {$user->user_login} ({$user->ID}) from " . site_url() . '.' );
+			WP_CLI::success( "Removed all roles from {$user->user_login} ({$user->ID})." );
 		}
 	}