feat(CategoryTheory): the category of ind-objects is Grothendieck abelian

[TwoFX]

• If C is small and additive, then Ind C is preadditive (which implies that it is additive using existing results)
• If C is small and abelian, then Ind C is Grothendieck abelian

---

• depends on: [Merged by Bors] - feat(CategoryTheory): forgetting the group structure on the codomain of left-exact functors #21973

[github-actions]

PR summary 82e41fcb8d

Import changes exceeding 2%

%	File
+6.66%	Mathlib.CategoryTheory.Abelian.GrothendieckAxioms.Indization
+30.00%	Mathlib.CategoryTheory.Generator.Indization

Import changes for modified files

Dependency changes

File	Base Count	Head Count	Change
Mathlib.CategoryTheory.Generator.Indization	760	988	+228 (+30.00%)
Mathlib.CategoryTheory.Abelian.GrothendieckAxioms.Indization	991	1057	+66 (+6.66%)

Import changes for all files

Files	Import difference
Mathlib.CategoryTheory.Abelian.GrothendieckAxioms.Indization	66
Mathlib.CategoryTheory.Generator.Indization	228
Mathlib.CategoryTheory.Preadditive.Indization (new file)	972
Mathlib.CategoryTheory.Abelian.Indization (new file)	984

---

Declarations diff

+ Ind.isSeparator_range_yoneda
+ instance : Abelian (Ind C)
+ instance : HasFiniteBiproducts (Ind C)
+ instance : Preadditive (Ind C)
+ instance {X Y : Ind C} (f : X ⟶ Y) : IsIso (Abelian.coimageImageComparison f) := by
+ isGrothendieckAbelian_ind

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.

---

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).

[mathlib4-dependent-issues-bot]

This PR/issue depends on:

• [Merged by Bors] - feat(CategoryTheory): forgetting the group structure on the codomain of left-exact functors #21973
  By Dependent Issues (🤖). Happy coding!