[Merged by Bors] - chore: use the positivity [h, h'] syntax when useful

[grunweg]

Since #30388, have := foo; positivity can be shortened to positivity [foo].
Make use of that when sensible.

I searched for all occurrences of have :.*\n\s*positi (using VS Code, i.e. using rg internally) and inspected them manually. In a few cases, keeping the have separate seemed more readable to me.

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[github-actions]

PR summary 94c059e90a

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference

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Declarations diff

No declarations were harmed in the making of this PR! 🐙

You can run this locally as follows

## summary with just the declaration names:
./scripts/declarations_diff.sh <optional_commit>

## more verbose report:
./scripts/declarations_diff.sh long <optional_commit>

The doc-module for script/declarations_diff.sh contains some details about this script.

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No changes to technical debt.

You can run this locally as

./scripts/technical-debt-metrics.sh pr_summary

• The relative value is the weighted sum of the differences with weight given by the inverse of the current value of the statistic.
• The absolute value is the relative value divided by the total sum of the inverses of the current values (i.e. the weighted average of the differences).

[leanprover-community-mathlib4-bot]

!bench

[leanprover-bot]

Here are the benchmark results for commit 562c75f.
There were no significant changes against commit 94c059e.

[github-actions]

File	Instructions	%
build	-2.523⬝10⁹	(+0.00%)
CI run Lakeprof report

[j-loreaux]

Yes, please! And thank you!

Can you please add a short blurb in the PR description saying how you found these occurrences? Was it just grep? It would be nice if we had a systematic way to find all of them, as I think there are surely more than this.

bors d+

[mathlib-bors]

✌️ grunweg can now approve this pull request. To approve and merge a pull request, simply reply with bors r+. More detailed instructions are available here.

[grunweg]

Yes, I grepped (added that to the PR description) --- and just realised why I only found so few hits. Thanks for the inspiration, follow-up incoming :-)

[grunweg]

bors merge

[grunweg]

Update: searching for have .*\n\s*positi yields one more actionable location (and 14 others). Am I overlooking something, or are there indeed only this few places?

[grunweg]

Filed the follow-up as #30656.

[mathlib-bors]

Pull request successfully merged into master.

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