Corrections to docs for intersphinx

[SaashaJoshi]

Things corrected in this PR:

• Prepend dot (.) to internal class references. (Resolves Prepend many Sphinx class/func/mod cross references with a dot #216 )
• Remove redundant :external: keyword from external class references
• Add documentation links for qiskit-nature, qiskit-ibm-runtime, and qiskit-aer.

Things to look into:

- [ ] Interlink modules and attributes.

• Reference to non-existing EntanglementForgingVQE class in entanglement_forging_operator (line 27).

https://github.com/Qiskit-Extensions/circuit-knitting-toolbox/blob/c5207b191b601223e8e4e5eb56b2200c256101e7/circuit_knitting/forging/entanglement_forging_operator.py#L22-L28

Related to:
Resolves #215

[coveralls]

Pull Request Test Coverage Report for Build 5521456168

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 90.703%

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Totals
Change from base Build 5520136589:	0.0%
Covered Lines:	2556
Relevant Lines:	2818

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💛 - Coveralls

[garrison]

Does doing this alone allow any links to work that did not work before? I am curious. (We might have to prefix each identifier once with :external for it to be picked up.)

[SaashaJoshi]

Does doing this alone allow any links to work that did not work before? I am curious. (We might have to prefix each identifier once with :external for it to be picked up.)

I realized we do not need :external anywhere. The interlinking works without it as well (I will make this change in the next commit).
However, I see that the internal classes like :class: TwoQubitQPDGate do not get linked; I am still figuring out this one.

[garrison]

However, I see that the internal classes like :class: TwoQubitQPDGate do not get linked; I am still figuring out this one.

It might be enough to say :class:`.TwoQubitQPDGate`, i.e., to prepend it with a dot each time it is mentioned.

[garrison]

Related to:
#215

I think this may actually close #215. Is there anything left to do after the current PR?

EDIT: wait, I see: you've already adjusted this in the bulleted list. Nevermind! 🙂

[SaashaJoshi]

I also made edit for #216 . I realized that issue was also covered in this PR.

[garrison]

Thanks -- this looks great!