Reformat source code with Prettier 1.5.2

packages/react-dev-utils/webpackHotDevClient.js

@@ -81,14 +81,16 @@ function addOverlayDivTo(iframe) {
 }
 
 function overlayHeaderStyle() {
-  return 'font-size: 2em;' +
+  return (
+    'font-size: 2em;' +
     'font-family: sans-serif;' +
     'color: rgb(206, 17, 38);' +
     'white-space: pre-wrap;' +
     'margin: 0 2rem 0.75rem 0px;' +
     'flex: 0 0 auto;' +
     'max-height: 35%;' +
-    'overflow: auto;';
+    'overflow: auto;'
+  );
 }
 
 var overlayIframe = null;
@@ -127,7 +129,8 @@ function ensureOverlayDivExists(onOverlayDivReady) {
 function showErrorOverlay(message) {
   ensureOverlayDivExists(function onOverlayDivReady(overlayDiv) {
     // TODO: unify this with our runtime overlay
-    overlayDiv.innerHTML = '<div style="' +
+    overlayDiv.innerHTML =
+      '<div style="' +
       overlayHeaderStyle() +
       '">Failed to compile</div>' +
       '<pre style="' +