minor changes

Author: Mash707

packages/react-charts/src/victory/components/ChartTooltip/examples/ChartTooltipCssOverflow.tsx

@@ -13,11 +13,11 @@ interface PetData {
 }
 
 export const ChartTooltipCssOverflow: React.FunctionComponent = () => {
-  const sheet = (() => {
+  const sheet = () => {
     const style = document.createElement('style');
     document.head.appendChild(style);
     return style.sheet;
-  })();
+  };
 
   sheet.insertRule(
     '.ws-react-charts-tooltip-overflow { margin-left: 50px; margin-top: 50px; height: 135px; }',