Improve the list of supported terminal sequences

[soegaard]

One of the most important pages in the documentation is the list of supported terminal sequences:

https://xtermjs.org/docs/api/vtfeatures/

There are quite a few commands, so I use hit cmd-f and use the find-on-page feature of the browser to find the command I need.

But ... some things are hidden away in behind the word "more" - which means the find-feature can not find the relevant command. Anecdotally, it took me forever to find the command to switch between the alternate and the normal buffer. [I knew it was possible because the alternate buffer was mentioned in the code.]

Turns out the information is hidden behind the "more" for:

DECSET - Set various terminal attributes. 

The feature request is thus a button that unfolds all "more" links at once,
so I can use find-on-page to find "obscure" commands.