Add support for generic intrinsic expressions and statements.

[dtzSiFive]

Contributor Checklist

• Did you add Scaladoc to every public function/method?
• Did you add at least one test demonstrating the PR?
• Did you delete any extraneous printlns/debugging code?
• Did you specify the type of improvement?
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Type of Improvement

• Feature (or new API)

Desired Merge Strategy

• Squash: The PR will be squashed and merged (choose this if you have no preference).

Release Notes

Intrinsic expressions and statements are now supported, streamlining their use. These should be preferred over intrinsicModule's, which in the future will be deprecated and removed.

Reviewer Checklist (only modified by reviewer)

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• Did you mark the proper milestone (Bug fix: 3.6.x, 5.x, or 6.x depending on impact, API modification or big change: 7.0)?
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• Did you do one of the following when ready to merge:
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[dtzSiFive]

FWIW, example moving SizeOf from intmodule to intrinsic expression: dtzSiFive@3bdab7c
(slightly tweaked things but same idea as shown there 👍)

[jackkoenig]

Generally looks great, see comments, especially the one about Map and ordering.

[jackkoenig]

LGTM, I'll leave it to your judgement on the API being Map + sorting vs. ordered (but at least note the sorting in the ScalaDoc if that's your decision). Also see minor comment about ScalaDoc style.