message: Handle BigEmoji permalinks better
  Now that permalinks could be not-matrix.to we should be safer in what we'll allow.
diff: @@ -447,10 +447,12 @@ export function bodyToHtml(content, highlights, opts={}) {
  const match = BIGEMOJI_REGEX.exec(contentBodyTrimmed);
  emojiBody = match && match[0] && match[0].length === contentBodyTrimmed.length &&
  // Prevent user pills expanding for users with only emoji in
  - // their username
  + // their username. Permalinks (links in pills) can be any URL
  + // now, so we just check for an HTTP-looking thing.
  (
  content.formatted_body == undefined ||
  - !content.formatted_body.includes("https://matrix.to/")
  + !content.formatted_body.includes("http:") ||
  + !content.formatted_body.includes("https:")
  );
  }
  