add pubment after-create-new-drracket-frame and after-create-new-tab

[Metaxal]

New pubment methods to be used in next PRs by Quickscript.

[Metaxal]

Currently the queue-callback for create-new-drracket-frame is in quickscript, but I wonder whether it should be in the pubment method instead.

[rfindler]

I think we need documentation too.

Why is there a guard on filename for the call to after-create-new-tab?

[Metaxal]

Yes, docs, will do.

For filename, I wanted to call the hook only when an empty new tab is created. For loading file, I think augmenting on-file-load in editor<%> is more appropriate.

That said, the pubment method could well accept all the same arguments, and QS could do the guarding itself. Would you prefer this option?

[rfindler]

I don't have a strong opinion on any specific timing of the callbacks, actually, just as long as the entire set makes some sense together is all. I guess the docs will clarify it all, then!

[Metaxal]

As the message says, I removed the filename guard and added the docs. LMKWYT.