Add release note for Expr support

[jakelishman]

Summary

Close #10331.

Details and comments

[qiskit-bot]

One or more of the the following people are requested to review this:

• @Qiskit/terra-core

[Eric-Arellano]

Lgtm from a wording perspective :)

[Eric-Arellano]

Nit, Python uses lowercase

Suggested change

	These can act on Python integer and Boolean literals, or on :class:`.ClassicalRegister`
	These can act on Python integer and boolean literals, or on :class:`.ClassicalRegister`

[jakelishman]

We capitalise most adjectives derived from proper nouns (Gaussian, Laplacian, Jacobian, etc), and Qiskit's mostly just inconsistent on "Boolean" in particular. I don't really know why we don't afford George Boole the same courtesy as others ;). At any rate, in all documentation I've written for Qiskit, I've capitalised it.

[jakelishman]

Fwiw, even python.org is inconsistent on this: both forms of capitalisation are present on https://docs.python.org/3/library/stdtypes.html, say.

[Eric-Arellano]

"bear with us" is a weird English idiom. Maybe this to be more accessible to non-native speakers?

Suggested change

	support expressions that look simple in Qiskit. Please bear with us, and your hardware vendors!
	support expressions that look simple in Qiskit. Please be patient with us and your hardware vendors!

[jakelishman]

I can change it if you think it's much better, but "endure" is a common meaning of "bear" ("I can bear the pain" / "I couldn't bear the experience") - I wouldn't disagree that "bear with us" is idiomatic, but I would disagree that it's weird or unusual.

[mtreinish]

Personally I would have worded this a bit more formally I don't take too much issue with the use of ":bear: with us" as an idiom (as long as we use the proper character :P ), but more I'd have said something like:

This feature is new for both Qiskit and the available quantum hardware that Qiskit works with. As the features are still being developed there are likely to be places where there are unexpected edge cases that will need some time to be worked out. If you encounter any issue around classical expression support or usage please open an issue with Qiskit or your hardware vendor.

[jakelishman]

yeah, that's probably better than what I wrote

[Eric-Arellano]

I'm fine if you want to stick with bear.

[coveralls]

Pull Request Test Coverage Report for Build 5669229161

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 6 unchanged lines in 3 files lost coverage.
• Overall coverage increased (+0.02%) to 85.92%

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Files with Coverage Reduction	New Missed Lines	%
qiskit/extensions/unitary.py	1	93.75%
crates/qasm2/src/lex.rs	2	90.89%
qiskit/pulse/library/waveform.py	3	93.75%

Totals
Change from base Build 5667924881:	0.02%
Covered Lines:	73037
Relevant Lines:	85006

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💛 - Coveralls

[mtreinish]

I had some comments inline about the separation of the release notes. None are critical or worth blocking over though because we can easily adjust it post-backport in #10497.

[mtreinish]

Personally I would have worded this a bit more formally I don't take too much issue with the use of ":bear: with us" as an idiom (as long as we use the proper character :P ), but more I'd have said something like:

This feature is new for both Qiskit and the available quantum hardware that Qiskit works with. As the features are still being developed there are likely to be places where there are unexpected edge cases that will need some time to be worked out. If you encounter any issue around classical expression support or usage please open an issue with Qiskit or your hardware vendor.

[mtreinish]

This reads like a continuation of the above release note should it really be in a separate note?

[jakelishman]

I don't feel super strongly, but I approximately considered them separate parts of the feature. If you think it'll be better to combine all three, that's fine by me.

[mtreinish]

I think it's fine to have it as a separate note, as I agree it's a separate feature. It was more just the wording here starts with "In addition" and the tone sounds like it's part of the previous note instead of describing just the expression visitor class and what it's used for and how it's used.

[jakelishman]

That's fair. Want me to fix it here (since it's not in the mergeable part of the queue anyway) or wait til fixup later?

[mtreinish]

Oh I missed the question here until now and it's the head of the merge queue. Lets just fix it as part of #10497 at this point.

[mtreinish]

Same question here the flow between these notes seem like they're just separate paragraphs of the same release note instead of separate bullet points in the features section. I know reno puts them all together since they're in the same file as function of how it generates the rst output. But, I always try to think of separate notes as if they order will be shuffled when they're assembled, and in this case I feel like this (and even more so with the above note) they wouldn't be able to stand on their own if they were shuffled.