Support URI Text Fragments in Firefox, Safari

URI text fragment like https://archive.org/details/goody/page/6/mode/2up#:~:text=Poor%20at%20the,Parifh work in Chrome out-of-the-box thanks to the text layer. But in Firefox / Safari, they don't show up. I believe this is because the text layer hasn't been fetched/rendered yet. In order to get this to work, I imagine we'd need to speed up the initial BR rendering.