feat(FinitelyPresentedGroup): add definitional equivalence with generating set given by S : Set G

[AlecsFerra]

cc @homeowmorphism

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[github-actions]

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[github-actions]

PR summary 98200fe16e

Import changes exceeding 2%

%	File
+47.59%	Mathlib.GroupTheory.FinitelyPresentedGroup

Import changes for modified files

Dependency changes

File	Base Count	Head Count	Change
Mathlib.GroupTheory.FinitelyPresentedGroup	519	766	+247 (+47.59%)

Import changes for all files

Files	Import difference
Mathlib.GroupTheory.FinitelyPresentedGroup	247

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Declarations diff

+ iff_hom_surj_set_G
+ of_hom_surj_finite

You can run this locally as follows

## from your `mathlib4` directory:
git clone https://github.com/leanprover-community/mathlib-ci.git ../mathlib-ci

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

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

The doc-module for scripts/pr_summary/declarations_diff.sh in the mathlib-ci repository contains some details about this script.

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No changes to strong technical debt.

No changes to weak technical debt.

Current commit 98200fe16e
Reference commit e577c1669e

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).