unique react key in playground editor buttons (#29836)

* unique React key in playground editor buttons

* second place

components/playground/CodeLanguagePicker.tsx

@@ -13,6 +13,7 @@ export const CodeLanguagePicker = () => {
       <SubNav.Links>
         {codeLanguages.map((language) => (
           <SubNav.Link
+            key={language.id}
             as={Link}
             href={`${routePath}?langId=${language.id}`}
             selected={language.id === currentLanguage.id}

components/playground/editor/Editor.tsx

@@ -74,6 +74,7 @@ export const Editor: React.FC<Props> = ({ article }) => {
           {editorFiles.map((file, i) => {
             return (
               <button
+                key={file.fileName}
                 className={cx('btn-link Link--secondary no-underline mr-2 f6 py-2 px-3', {
                   'color-bg-subtle': i === selectedFileIndex,
                 })}