[Merged by Bors] - chore(Algebra/Ring/Invertible): golf a proof using grind

[yuanyi-350]

Trace profiling results:

neg_one_eq_invOf_mul_add_invOf_mul_iff: 50 ms before, <12 ms after 🎉
Profiled using set_option trace.profiler true in.

[github-actions]

PR summary c14b4ac5be

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference

---

Declarations diff (regex)

No declarations were harmed in the making of this PR! 🐙

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 -- unavailable)

⚠️ No declarations diff yet: there is no built master snapshot at this PR's merge-base (typically a bors-batch intermediate that CI never built). Merge master into this PR and push to refresh.

---

No changes to strong technical debt.

No changes to weak technical debt.

Current commit c14b4ac5be
Reference commit ca0ba44e15

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).

[Whysoserioushah]

!radar

[leanprover-radar]

Benchmark results for c14b4ac against ca0ba44 are in. No significant results found. @Whysoserioushah

• 🟥 build//instructions: +335.5M (+0.00%)

Small changes (1✅)

• ✅ build/module/Mathlib.AlgebraicGeometry.Sites.ElladicCohomology//instructions: -680.0M (-0.52%)

[Whysoserioushah]

The general slowdown should just be noise, LGTM!

[themathqueen]

maintainer merge

[github-actions]

🚀 Pull request has been placed on the maintainer queue by themathqueen.

[grunweg]

Thanks!
bors merge

[mathlib-bors]

Pull request successfully merged into master.

Build succeeded:

• ci (staging) / Build
• ci (staging) / Test and lint
• ci (staging) / Lint style
• ci (staging) / Post-Build Step
• ci (staging) / Post-CI job