When a website updates its page title dynamically or uses AJAX for page navigation, the page title when the player started might be outdated

BUG: 395393

I get proper page title in Spotify now when pressing play, however, when pausing it now changes to e.g. "Search" but it's either this, or that, so I'd rather have the current page title there. Might also fix some woes on YouTube where it uses Ajax page navigation in playlists

Host part would be 5.13 as it's quite non-invasive. Might print a warning about how "titlechange" isn't known when running newer extension with older host but it won't break anything and I don't think using the plugin versioning for this is worth it