refactor: convert function expressions to declarations (#4926)

packages/netlify-cms-widget-text/src/TextPreview.js

@@ -2,7 +2,9 @@ import React from 'react';
 import PropTypes from 'prop-types';
 import { WidgetPreviewContainer } from 'netlify-cms-ui-default';
 
-const TextPreview = ({ value }) => <WidgetPreviewContainer>{value}</WidgetPreviewContainer>;
+function TextPreview({ value }) {
+  return <WidgetPreviewContainer>{value}</WidgetPreviewContainer>;
+}
 
 TextPreview.propTypes = {
   value: PropTypes.node,

packages/netlify-cms-widget-text/src/index.js

@@ -1,12 +1,14 @@
 import controlComponent from './TextControl';
 import previewComponent from './TextPreview';
 
-const Widget = (opts = {}) => ({
-  name: 'text',
-  controlComponent,
-  previewComponent,
-  ...opts,
-});
+function Widget(opts = {}) {
+  return {
+    name: 'text',
+    controlComponent,
+    previewComponent,
+    ...opts,
+  };
+}
 
 export const NetlifyCmsWidgetText = { Widget, controlComponent, previewComponent };
 export default NetlifyCmsWidgetText;