[show-hint addon] Scroll initially selected hint into view

See https://discuss.codemirror.net/t/show-selectedhint-in-very-long-list-of-hints/2255

Author: marijnh

addon/hint/show-hint.js

@@ -322,6 +322,7 @@
     CodeMirror.on(hints, "mousedown", function() {
       setTimeout(function(){cm.focus();}, 20);
     });
+    this.scrollToActive()
 
     CodeMirror.signal(data, "select", completions[this.selectedHint], hints.childNodes[this.selectedHint]);
     return true;
@@ -363,11 +364,16 @@
       if (node) node.className = node.className.replace(" " + ACTIVE_HINT_ELEMENT_CLASS, "");
       node = this.hints.childNodes[this.selectedHint = i];
       node.className += " " + ACTIVE_HINT_ELEMENT_CLASS;
+      this.scrollToActive()
+      CodeMirror.signal(this.data, "select", this.data.list[this.selectedHint], node);
+    },
+
+    scrollToActive: function() {
+      var node = this.hints.childNodes[this.selectedHint]
       if (node.offsetTop < this.hints.scrollTop)
         this.hints.scrollTop = node.offsetTop - 3;
       else if (node.offsetTop + node.offsetHeight > this.hints.scrollTop + this.hints.clientHeight)
         this.hints.scrollTop = node.offsetTop + node.offsetHeight - this.hints.clientHeight + 3;
-      CodeMirror.signal(this.data, "select", this.data.list[this.selectedHint], node);
     },
 
     screenAmount: function() {