Fix qiskit.circuit method header and broken cross-reference (backport #12394)

[mergify]

Part of Qiskit/documentation#1275

The __array__ method has a wrong header in the API docs (as we can see in the following screenshot) because Sphinx is not able to set the correct id in the generated HTML for methods starting with double underscore. Instead, Sphinx truncates the name to array__.

This PR changes the method to be instead builtins.__array__, and it also fixes a broken reference for Instruction.params. The cross-reference was broken due to the .. currentmodule:: None directive.

This is the result of Sphinx after this PR:

The API docs will have the correct header because we only use the part after the last dot in the id.

The PR will need backport to stable/1.1

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This is an automatic backport of pull request #12394 done by Mergify.

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[coveralls]

Pull Request Test Coverage Report for Build 9121601643

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 19 unchanged lines in 3 files lost coverage.
• Overall coverage decreased (-0.01%) to 89.607%

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Files with Coverage Reduction	New Missed Lines	%
crates/qasm2/src/expr.rs	1	94.02%
crates/qasm2/src/lex.rs	6	92.37%
crates/qasm2/src/parse.rs	12	97.15%

Totals
Change from base Build 9117917188:	-0.01%
Covered Lines:	62248
Relevant Lines:	69468

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💛 - Coveralls