main.js: give type signatures to a few helper functions

Author: lolbinarycat

src/librustdoc/html/static/js/main.js

@@ -322,7 +322,6 @@ function preLoadCss(cssUrl) {
 search=window.searchState.outputElement();
 }
 switchDisplayedElement(search);
-window.searchState.mouseMovedAfterSearch=false;
 document.title=window.searchState.title;
 },
 removeQueryParameters: ()=>{
@@ -499,17 +498,22 @@ function preLoadCss(cssUrl) {
 handleHashes(ev);
 }
 
-// @ts-expect-error
+/**
+ * @param {HTMLElement|null} elem
+ */
 functionopenParentDetails(elem){
 while(elem){
 if(elem.tagName==="DETAILS"){
+// @ts-expect-error
 elem.open=true;
 }
-elem=elem.parentNode;
+elem=elem.parentElement;
 }
 }
 
-// @ts-expect-error
+/**
+ * @param {string} id
+ */
 functionexpandSection(id){
 openParentDetails(document.getElementById(id));
 }