`Equivalence` for `≡` on gmultisets.

7 jobs for master in 20 minutes and 10 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #10592
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build-coq.8.6.0

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build-coq.8.6.1

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build-coq.8.7.0

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build-coq.8.7.1

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build-coq.8.7.2

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build-coq.8.8.dev

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build-coq.dev

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