ConverseJS: Remove spoilers as it is buggy.

CHANGELOG.md

@@ -1,5 +1,12 @@
 # Changelog
 
+## Unreleased Yet
+
+### Features
+
+* Using ConverseJS 9.0.0 (instead of 7.0.6).
+  * NB: the «spoiler» function is disabled, as it is buggy in ConverseJS 9.0.0 (see <https://github.com/conversejs/converse.js/issues/2627>)
+
 ## 5.1.0
 
 ### Features

conversejs/builtin.ts

@@ -143,7 +143,7 @@ window.initConverse = async function initConverse ({
     allow_message_retraction: 'all',
     visible_toolbar_buttons: {
       call: false,
-      spoiler: true,
+      spoiler: false,
       emoji: true,
       toggle_occupants: true
     },