feat(LinearAlgebra/Matrix/GeneralLinear/Projective): add iso between psl and pgl when algebraically closed

[Whysoserioushah]

This PR is split and generalised from FLT#1020

---

[github-actions]

PR summary 2f0fc072da

Import changes exceeding 2%

%	File
+11.56%	Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Projective

Import changes for modified files

Dependency changes

File	Base Count	Head Count	Change
Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Projective	1575	1757	+182 (+11.56%)

Import changes for all files

Files	Import difference
6 files Mathlib.Analysis.Complex.UpperHalfPlane.Manifold Mathlib.Analysis.Complex.UpperHalfPlane.Measure Mathlib.NumberTheory.ModularForms.EisensteinSeries.E2.Defs Mathlib.NumberTheory.ModularForms.EisensteinSeries.MDifferentiable Mathlib.NumberTheory.ModularForms.JacobiTheta.Manifold Mathlib.NumberTheory.ModularForms.JacobiTheta.OneVariable	1
Mathlib.NumberTheory.ModularForms.EisensteinSeries.IsBoundedAtImInfty	24
Mathlib.NumberTheory.ModularForms.BoundedAtCusp	25
Mathlib.NumberTheory.ModularForms.Identities	26
3 files Mathlib.Analysis.Complex.UpperHalfPlane.ProperAction Mathlib.NumberTheory.ModularForms.EisensteinSeries.UniformConvergence Mathlib.NumberTheory.ModularForms.ProperlyDiscontinuous	27
3 files Mathlib.Analysis.Complex.UpperHalfPlane.FixedPoints Mathlib.NumberTheory.ModularForms.EisensteinSeries.Defs Mathlib.NumberTheory.ModularForms.SlashInvariantForms	29
Mathlib.Analysis.SpecialFunctions.Trigonometric.Cotangent	117
Mathlib.NumberTheory.ModularForms.EisensteinSeries.Summable Mathlib.NumberTheory.Modular	125
Mathlib.Analysis.Complex.UpperHalfPlane.Metric	161
Mathlib.Analysis.Complex.UpperHalfPlane.FunctionsBoundedAtInfty Mathlib.Analysis.Complex.UpperHalfPlane.Topology	170
Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction Mathlib.NumberTheory.ModularForms.SlashActions	171
Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Projective	182

---

Declarations diff (regex)

+ _root_.Matrix.ProjectiveSpecialLinearGroup.toPGL
+ _root_.Matrix.ProjectiveSpecialLinearGroup.toPGL_injective
+ _root_.Matrix.ProjectiveSpecialLinearGroup.toPGL_mk
+ _root_.Matrix.ProjectiveSpecialLinearGroup.toPGL_surj_of_roots
+ isoPSLOfAlgClosed
+ mk_eq_mk_iff
+ mk_eq_mk_iff'

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.

Declarations diff (Lean)

✅ Lean-aware diff — post-build, computed from the Lean environment (commit 2f0fc07).

• +7 new declarations
• −0 removed declarations

+Matrix.ProjGenLinGroup.isoPSLOfAlgClosed
+Matrix.ProjGenLinGroup.mk_eq_mk_iff
+Matrix.ProjGenLinGroup.mk_eq_mk_iff'
+Matrix.ProjectiveSpecialLinearGroup.toPGL
+Matrix.ProjectiveSpecialLinearGroup.toPGL_injective
+Matrix.ProjectiveSpecialLinearGroup.toPGL_mk
+Matrix.ProjectiveSpecialLinearGroup.toPGL_surj_of_roots

---

No changes to strong technical debt.

No changes to weak technical debt.

Current commit 2f0fc072da
Reference commit 6923f2f175

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).