[Merged by Bors] - refactor(GroupTheory/PGroup,Sylow): Replace Fintype.card with Nat.card

[tb65536]

A lot of the group theory library still needs to be switched over from Fintype.card to Nat.card. This PR switches over GroupTheory/PGroup.lean and GroupTheory/Sylow (there was enough dependence between the two that it was simplest to do them together).

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[github-actions]

PR summary 36856c7b14

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

+ Sylow.finite_of_injective
+ Sylow.finite_of_ker_is_pGroup
+ _root_.exists_prime_orderOf_dvd_card'
+ instance (H : Subgroup G) [Finite (Sylow p G)] : Finite (Sylow p H)
+ instance [Fact p.Prime] [Finite (Sylow p G)] (P : Sylow p G) :
+ isCyclic_of_card_dvd_prime
- Sylow.fintypeOfInjective
- Sylow.fintypeOfKerIsPGroup
- instance (H : Subgroup G) [Finite (Sylow p G)] : Finite (Sylow p H) := by
- instance (H : Subgroup G) [Fintype (Sylow p G)] : Fintype (Sylow p H)
- instance [Fact p.Prime] [Fintype (Sylow p G)] (P : Sylow p G) :

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>

[jcommelin]

Thanks 🎉

bors merge

[mathlib-bors]

Pull request successfully merged into master.

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