[No QA] Add clarification notes on datepicker

src/components/DatePicker/index.ios.js

@@ -130,4 +130,10 @@ class Datepicker extends React.Component {
 Datepicker.propTypes = datepickerPropTypes;
 Datepicker.defaultProps = defaultProps;
 
+/**
+ * We're applying localization here because we present a modal (with buttons) ourselves
+ * Furthermore we're passing the locale down so that the modal and the date spinner are in the same
+ * locale. Otherwise the spinner would be present in the system locale and it would be weird if it happens
+ * that the modal buttons are in one locale (app) while the (spinner) month names are another (system)
+ */
 export default withLocalize(Datepicker);

src/components/DatePicker/styles.css

@@ -1,3 +1,10 @@
+/**
+ * Using a .css file is a special case here, because it's impossible to target
+ * pseudo-elements from js code (e.g. ::-webkit)
+ * It also helps in cases like using the Datepicker in Storybook - the styles are imported
+ * with the component
+ */
+
 .expensify-datepicker::-webkit-calendar-picker-indicator {
     position: absolute;
     right: 12px;