Add the jsx-a11y/lang rule to the recommended and strict presets

Author: astorije

README.md

@@ -150,6 +150,7 @@ Rule | Recommended | Strict
 [img-redundant-alt](https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/img-redundant-alt.md) | error | error
 [interactive-supports-focus](https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/interactive-supports-focus.md) | error | error
 [label-has-associated-control](https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/label-has-associated-control.md) | error | error
+[lang](https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/lang.md) | error | error
 [media-has-caption](https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/media-has-caption.md) | error | error
 [mouse-events-have-key-events](https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/mouse-events-have-key-events.md) | error | error
 [no-access-key](https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/no-access-key.md) | error | error

src/index.js

@@ -110,6 +110,7 @@ module.exports = {
         ],
         'jsx-a11y/label-has-associated-control': 'error',
         'jsx-a11y/label-has-for': 'off',
+        'jsx-a11y/lang': 'error',
         'jsx-a11y/media-has-caption': 'error',
         'jsx-a11y/mouse-events-have-key-events': 'error',
         'jsx-a11y/no-access-key': 'error',
@@ -267,6 +268,7 @@ module.exports = {
         ],
         'jsx-a11y/label-has-for': 'error',
         'jsx-a11y/label-has-associated-control': 'error',
+        'jsx-a11y/lang': 'error',
         'jsx-a11y/media-has-caption': 'error',
         'jsx-a11y/mouse-events-have-key-events': 'error',
         'jsx-a11y/no-access-key': 'error',