docs: add deferred, range, e, and pi to API reference

[tswast]

Description of changes

Some top-level APIs were missing from the API reference. This adds them.

[tswast]

Re: file:///home/runner/work/ibis/ibis/docs/_output/reference/range | Failed: Cannot find file. I'll try some fixes. Adding a more specific package name seemed to help for the others.

[cpcloud]

That means that there's a file referenced somewhere that doesn't exist. That usually means that wherever you're referencing range, the way you've referenced it is incorrect.

[cpcloud]

Ah, looks like you're not referencing range anywhere, so that may not be the issue.

[gforsyth]

Looks like the docstring for ibis.range has an invalid link -- let me poke it

[gforsyth]

I was wrong about interlinks, we do have them, so it may just be how we're spelling it. Poking locally, still

[tswast]

Thanks @gforsyth I see you're updating the PR.

Looks like https://docs.python.org/3/library/functions.html#func-range would be the right link, but yeah if interlinks work it would be good to reference the built-in that way.

[gforsyth]

ok, that took way too long to figure out, but it's rendering correctly for me now