chore(Order/Hom/Basic): fix EquivLike OrderIso instance diamond

[SnirBroshi]

OrderIso is an abbrev for RelIso which already has an EquivLike instance.
Removing it creates issues with to_dual, so instead we make it defeq to the RelIso instance using inferInstance.

Zulip

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[github-actions]

PR summary 10a055a908

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/pr_summary/declarations_diff.sh <optional_commit>

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

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

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No changes to technical debt.

This script lives in the mathlib-ci repository. To run it locally, from your mathlib4 directory:

git clone https://github.com/leanprover-community/mathlib-ci.git ../mathlib-ci
../mathlib-ci/scripts/reporting/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).

[SnirBroshi]

Hmm, the errors are all due to to_dual having an issue translating a proof:

@[to_dual] failed to insert a cast to make `...` applied to `...` well typed

[JovanGerb]

Thanks!

maintainer merge

[github-actions]

🚀 Pull request has been placed on the maintainer queue by JovanGerb.