Update richtext values before htmx submits data

CKEditor automatically updates corresponding textarea values on form submit,
but htmx collects data before that, which causes submitted textarea values
to be outdated.

This commit explicitly updates textarea values before htmx submits, to get
around the issue.

share/static/js/util.js

@@ -1021,6 +1021,14 @@ document.addEventListener("htmx:load", function() {
             form.addClass('rt-form-submitted');
         });
     });
+
+    document.body.addEventListener('htmx:configRequest', function(evt) {
+        for ( const param in evt.detail.parameters ) {
+            if ( evt.detail.parameters[param + 'Type'] === 'text/html' && CKEDITOR.instances[param] ) {
+                evt.detail.parameters[param] = CKEDITOR.instances[param].getData();
+            }
+        }
+    });
 });
 
 function filterSearchResults () {