rustdoc: replace callback function with straight-line code

The `blurHandler` abstraction was only used once, and provided
little benefit over writing the code directly.

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

@@ -35,14 +35,6 @@ function elemIsInParent(elem, parent) {
     return false;
 }
 
-function blurHandler(event, parentElem, hideCallback) {
-    if (!elemIsInParent(document.activeElement, parentElem) &&
-        !elemIsInParent(event.relatedTarget, parentElem)
-    ) {
-        hideCallback();
-    }
-}
-
 window.rootPath = getVar("root-path");
 window.currentCrate = getVar("current-crate");
 
@@ -1045,7 +1037,12 @@ function preLoadCss(cssUrl) {
     }
 
     function helpBlurHandler(event) {
-        blurHandler(event, getHelpButton(), window.hidePopoverMenus);
+        const parentElem = getHelpButton();
+        if (!elemIsInParent(document.activeElement, parentElem) &&
+            !elemIsInParent(event.relatedTarget, parentElem)
+        ) {
+            window.hidePopoverMenus();
+        }
     }
 
     function buildHelpMenu() {