style(handsontable): add some comments

handsontable/src/core.js

@@ -19,7 +19,8 @@ import {
 } from './helpers/object';
 import { arrayFlatten, arrayMap, arrayEach, arrayReduce } from './helpers/array';
 import { toSingleLine } from './helpers/templateLiteralTag';
-import { getPlugin } from './plugins';
+// eslint-disable-next-line import/extensions
+import { getPlugin } from './plugins.js';
 import { getRenderer } from './renderers';
 import { getValidator } from './validators';
 import { randomString } from './helpers/string';

handsontable/src/plugins/nestedHeaders/nestedHeaders.js

@@ -9,7 +9,8 @@ import { arrayEach } from '../../helpers/array';
 import { objectEach } from '../../helpers/object';
 import { toSingleLine } from '../../helpers/templateLiteralTag';
 import { warn } from '../../helpers/console';
-import { registerPlugin } from '../../plugins';
+// eslint-disable-next-line import/extensions
+import { registerPlugin } from '../../plugins.js';
 import BasePlugin from '../_base';
 import { CellCoords } from '../../3rdparty/walkontable/src';
 import GhostTable from './utils/ghostTable';