Fix autoresize not working well in Firefox on page load

lib/TextArea/V5.js

@@ -12,6 +12,17 @@ CustomElement.create({
   onConnect: function () {
     this._textarea = this.querySelector("textarea");
     this._updateListener();
+
+    // In Firefox, for some reason, the `scrollHeight` property isn't correct
+    // when the component is connected. It is correct when the window loads, though,
+    // so we also perform a resize when that happens.
+    // We end up doing this in all browsers, but it's fine: the second resize is a no-op.
+    var self = this;
+    window.addEventListener("load", function () {
+      if (self._autoresize) {
+        self._resize();
+      }
+    });
   },
 
   observedAttributes: ["data-autoresize"],

src/Nri/Ui/TextArea/V5.elm

@@ -20,8 +20,9 @@ module Nri.Ui.TextArea.V5 exposing
 
 ### Patch changes
 
-  - no longer defaults the placeholder value to the label text
+  - No longer defaults the placeholder value to the label text
   - Adjust disabled styles
+  - Fix initial autoresize not working in Firefox
 
 
 ### Changes from V4