feed: reduce and censor content that has many newlines

Render newlines as linebreaks is nice, but it can be abused by
adding too many newlines. This change reduces 3 newlines to 2
globally to keep the output somewhat sane.

src/main.js

@@ -156,7 +156,7 @@ setInterval(() => {
 function createTextNote(evt, relay) {
   const {host, img, isReply, name, replies, time, userName} = getMetadata(evt, relay);
   const isLongContent = evt.content.trimRight().length > 280;
-  const content = isLongContent ? evt.content.slice(0, 280) : evt.content;
+  const content = (isLongContent ? evt.content.slice(0, 280) : evt.content).replaceAll(/\n{3,}/g, '\n\n');
   const hasReactions = reactionMap[evt.id]?.length > 0;
   const didReact = hasReactions && !!reactionMap[evt.id].find(reaction => reaction.pubkey === pubkey);
   const replyFeed = replies[0] ? replies.map(e => replyDomMap[e.id] = createTextNote(e, relay)) : [];