all: Use ->remove() instead of ->outertext = ''

simplehtmldom 1.9 introduced new functions to recursively remove
nodes from the DOM. This allows removing elements without the need
to re-load the document by using $html->load($html->save()), which
is very inefficient.

Find more information about remove() at
https://simplehtmldom.sourceforge.io/docs/1.9/api/simple_html_dom_node/remove/

bridges/TwitterBridge.php

@@ -171,7 +171,7 @@ class TwitterBridge extends BridgeAbstract {
 
 			// remove 'invisible' content
 			foreach($tweet->find('.invisible') as $invisible) {
-				$invisible->outertext = '';
+				$invisible->remove();
 			}
 
 			// Skip protmoted tweets