Auto merge of rust-lang#80554 - GuillaumeGomez:more-js-cleanup, r=jyn514

More js cleanup

Part of rust-lang#79052 (Same kind as rust-lang#80515).

This one is about some small fixes:
 * Replacing some loops with `onEachLazy`.
 * Removing unused function arguments.
 * Turn `buildHelperPopup` into a variable so it can be "replaced" once the function has been called once so it's not called again.

r? `@jyn514`

src/librustdoc/html/static/main.js

@@ -493,11 +493,7 @@ function defocusSearchBar() {
     document.addEventListener("keypress", handleShortcut);
     document.addEventListener("keydown", handleShortcut);
 
-    function resetMouseMoved(ev) {
-        mouseMovedAfterSearch = true;
-    }
-
-    document.addEventListener("mousemove", resetMouseMoved);
+    document.addEventListener("mousemove", function() { mouseMovedAfterSearch = true; });
 
     var handleSourceHighlight = (function() {
         var prev_line_id = 0;
@@ -2151,14 +2147,14 @@ function defocusSearchBar() {
                 var code = document.createElement("code");
                 code.innerHTML = struct.text;
 
-                var x = code.getElementsByTagName("a");
-                var xlength = x.length;
-                for (var it = 0; it < xlength; it++) {
-                    var href = x[it].getAttribute("href");
+                onEachLazy(code.getElementsByTagName("a"), function(elem) {
+                    var href = elem.getAttribute("href");
+
                     if (href && href.indexOf("http") !== 0) {
-                        x[it].setAttribute("href", rootPath + href);
+                        elem.setAttribute("href", rootPath + href);
                     }
-                }
+                });
+
                 var display = document.createElement("h3");
                 addClass(display, "impl");
                 display.innerHTML = "<span class=\"in-band\"><table class=\"table-display\">" +
@@ -2547,14 +2543,12 @@ function defocusSearchBar() {
             var hiddenElems = e.getElementsByClassName("hidden");
             var needToggle = false;
 
-            var hlength = hiddenElems.length;
-            for (var i = 0; i < hlength; ++i) {
-                if (hasClass(hiddenElems[i], "content") === false &&
-                    hasClass(hiddenElems[i], "docblock") === false) {
-                    needToggle = true;
-                    break;
+            var needToggle = onEachLazy(e.getElementsByClassName("hidden"), function(hiddenElem) {
+                if (hasClass(hiddenElem, "content") === false &&
+                    hasClass(hiddenElem, "docblock") === false) {
+                    return true;
                 }
-            }
+            });
             if (needToggle === true) {
                 var inner_toggle = newToggle.cloneNode(true);
                 inner_toggle.onclick = toggleClicked;