Doc fix ZZ_feature_maps (backport #13231)

[mergify]

Summary

I have added docstrings for data, entanglement_blocks, num_parameters, and parameters properties in the ZZ_Feature_Map documentation. Also, I updated the code example where to concatenate two circuits, the "+" has been replaced with the "compose" operation.
#Closes #12431

Details and comments

Also updated some formatting in the code example as the "copy to clipboard" button also copied the arrows which needed to be removed explicitly.

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This is an automatic backport of pull request #13231 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of f1b2580 has failed:

On branch mergify/bp/stable/1.2/pr-13231
Your branch is up to date with 'origin/stable/1.2'.

You are currently cherry-picking commit f1b25806e.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   qiskit/circuit/library/blueprintcircuit.py
	modified:   qiskit/circuit/library/data_preparation/pauli_feature_map.py

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   qiskit/circuit/library/data_preparation/zz_feature_map.py

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

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[coveralls]

Pull Request Test Coverage Report for Build 11156786770

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 16 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.005%) to 89.749%

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Files with Coverage Reduction	New Missed Lines	%
crates/qasm2/src/lex.rs	4	91.98%
crates/qasm2/src/parse.rs	12	97.15%

Totals
Change from base Build 11148098131:	-0.005%
Covered Lines:	66886
Relevant Lines:	74526

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💛 - Coveralls