Make missingbindings and allbindings deterministic

[IanButterworth]

See JuliaLang/julia#55267

[mortenpi]

I'm a bit confused by the changes / fix.

1. We now pass the checkdocs_ignored_modules when we gather the bindings.. which is probably fine, but it should be redundant, since doc.blueprint.modules should already be filtered?
2. I don't really understand why the sorting of keys would make a difference?

[IanButterworth]

1. Julia base docs only partially cover Pkg. Pkg has its own docs. So we need to pass Pkg for docs but exclude from the docs check

2. I don't either really. That part was Claude thinking random ordering was the reason for the random results

[mortenpi]

1. Julia base docs only partially cover Pkg. Pkg has its own docs. So we need to pass Pkg for docs but exclude from the docs check

But they should already be excluded by here, no?

Documenter.jl/src/documents.jl

Lines 521 to 524 in f887f34

	blueprint = DocumentBlueprint(
	Dict{String, Page}(),
	submodules(modules; ignore = Set(checkdocs_ignored_modules)),
	)

[IanButterworth]

@mortenpi I don't know. It might be worth investigating this with JuliaLang/julia#55267 without my guesses. This PR was necessary for me to get Pkg excluded

[fingolfin]

This probably should get a changelog entry?

I still don't quite understand why the sorting is needed, and that bothers me a bit; but in the end, I think we should be pragmatic: if both sort! are demonstrably necessary to solve a concrete problem in Julia, we probably should merge it anyway.

Perhaps with some code comments added in that explain why the sorting is done (as in: linking to this PR resp. to the underlying GitHub issue)?

[IanButterworth]

To be clearer, I don't know if these are the correct fixes, and I'm asking for help from devs more familiar with Documenter