Custom expression editor: avoid squiggly red lines (spellchecking) (#15402)

It does not make sense anyway for the web browser to suggest corrections
for function names etc.

frontend/src/metabase/query_builder/components/expressions/TokenizedInput.jsx

@@ -170,6 +170,7 @@ export default class TokenizedInput extends Component {
         className={className}
         style={{ ...style }}
         contentEditable
+        spellCheck={false}
         onKeyDown={
           this.props.tokenizedEditing
             ? this.onKeyDownTokenized