Sweep: add docstrings to React components

src/PersistentCheckbox.js

@@ -2,6 +2,13 @@ import { Component } from '@wordpress/element';
 
 import { getValue, setValue } from './localStorage';
 
+/**
+ * Renders a checkbox that persists its checked state in localStorage.
+ * 
+ * Props:
+ *   id (string): The unique ID of the checkbox. Used as the localStorage key.
+ *   label (React.Element): The label to display next to the checkbox.
+ */
 export default class PersistentCheckbox extends Component {
 	constructor( props ) {
 		super( props );

src/PersistentCheckboxList.js

@@ -2,6 +2,12 @@ import md5 from 'md5';
 
 import PersistentCheckbox from './PersistentCheckbox';
 
+/**
+ * Renders a list of PersistentCheckbox components.
+ *
+ * Props:
+ *   labels (string[]): An array of labels to render checkboxes for.
+ */
 export default function PersistentCheckboxList( { labels } ) {
 	const listId = `list-${ md5( labels.join( '' ) ) }`;
 	const style = { listStyleType: 'none', marginLeft: 0 };