Followup 1551320 - Port all of the createXULElement changes with extra comment

lib/CFRPageActions.jsm

@@ -402,7 +402,8 @@ class PageAction {
       }
       footerText.parentNode.appendChild(stepsContainer);
       for (let step of content.descriptionDetails.steps) {
-        const li = this.window.document.createElement("li");
+        // This li is a generic xul element with custom styling
+        const li = this.window.document.createXULElement("li");
         this._l10n.setAttributes(li, step.string_id);
         stepsContainer.appendChild(li);
       }