Fix some formatting inconsistencies

Run `prettier` on `frame-util.js` to fix up some minor formatting
inconsistencies.

src/annotator/util/frame-util.js

 'use strict';
 
 // Find all iframes within this iframe only
-function findFrames (container) {
+function findFrames(container) {
   const frames = Array.from(container.getElementsByTagName('iframe'));
   return frames.filter(isValid);
 }
 
 // Check if the iframe has already been injected
-function hasHypothesis (iframe) {
+function hasHypothesis(iframe) {
   return iframe.contentWindow.__hypothesis_frame === true;
 }
 
 // Inject embed.js into the iframe
-function injectHypothesis (iframe, scriptUrl, config) {
+function injectHypothesis(iframe, scriptUrl, config) {
   const configElement = document.createElement('script');
   configElement.className = 'js-hypothesis-config';
   configElement.type = 'application/json';
@@ -29,7 +29,7 @@ function injectHypothesis (iframe, scriptUrl, config) {
 }
 
 // Check if we can access this iframe's document
-function isAccessible (iframe) {
+function isAccessible(iframe) {
   try {
     return !!iframe.contentDocument;
   } catch (e) {
@@ -37,7 +37,6 @@ function isAccessible (iframe) {
   }
 }
 
-
 /**
  * Check if the frame elements being considered for injection have the
  * basic heuristics for content that a user might want to annotate.
@@ -48,21 +47,21 @@ function isAccessible (iframe) {
  * @param  {HTMLIFrameElement} iframe the frame being checked
  * @returns {boolean}   result of our validity checks
  */
-function isValid (iframe) {
-
+function isValid(iframe) {
   const isNotClientFrame = !iframe.classList.contains('h-sidebar-iframe');
 
   const frameRect = iframe.getBoundingClientRect();
   const MIN_WIDTH = 150;
   const MIN_HEIGHT = 150;
-  const hasSizableContainer = frameRect.width > MIN_WIDTH && frameRect.height > MIN_HEIGHT;
+  const hasSizableContainer =
+    frameRect.width > MIN_WIDTH && frameRect.height > MIN_HEIGHT;
 
   return isNotClientFrame && hasSizableContainer;
 }
 
-function isDocumentReady (iframe, callback) {
+function isDocumentReady(iframe, callback) {
   if (iframe.contentDocument.readyState === 'loading') {
-    iframe.contentDocument.addEventListener('DOMContentLoaded', function () {
+    iframe.contentDocument.addEventListener('DOMContentLoaded', function() {
       callback();
     });
   } else {
@@ -70,9 +69,9 @@ function isDocumentReady (iframe, callback) {
   }
 }
 
-function isLoaded (iframe, callback) {
+function isLoaded(iframe, callback) {
   if (iframe.contentDocument.readyState !== 'complete') {
-    iframe.addEventListener('load', function () {
+    iframe.addEventListener('load', function() {
       callback();
     });
   } else {