Startup always stacks up a new nyxt:help page each time

[Ambrevar]

If you restore sessions and keep nyxt:help open, notice how the page keeps stacking up.

This was not a problem before Lisp URLs because internal buffers were not persisted in the session.

Now I suppose that we should update the startup procedure to not fire up a new nyxt:help page if one is already restored.

@aartaka What do you think?

[aartaka]

Yes, that feels most intuitive!

[Ambrevar]

Actually it's a bit more subtle: help should not re-create a buffer if it finds another one with the same name in help-mode. And the problem is this: restored buffers don't restore their modes!!! :/

See #2064.

[aadcg]

This one seems critical.

[Ambrevar]

And also pretty easy to fix. @aartaka @aadcg @jmercouris Anyone motivated to work on it?

Forget it, forgot this depends on #2064. I'll work on it then :p

[aartaka]

#2627 could fix both #2064 and #1695, I believe.

[aadcg]

No longer important, due to #3598.