[Merged by Bors] - chore(Algebra/Group/Basic): rename mul_right_eq_self to mul_eq_left etc

[b-reinke]

See discussion of #22507, apparently mul_eq_left is used more often that mul_right_eq_self for the same kind of lemma.

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[github-actions]

PR summary 89340a3680

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

+ add_left_eq_self
+ add_left_ne_self
+ add_right_eq_self
+ add_right_ne_self
+ left_eq_mul
+ left_ne_mul
+ mul_eq_left
+ mul_eq_right
+ mul_ne_left
+ mul_ne_right
+ right_eq_mul
+ right_ne_mul
+ self_eq_add_left
+ self_eq_add_right
+ self_ne_add_left
+ self_ne_add_right

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.

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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).

[Paul-Lez]

Sorry for the slow review - this looks good to me!

[YaelDillies]

Thanks! 🚀

maintainer merge

[github-actions]

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

[kim-em]

bors merge

[mathlib-bors]

Pull request successfully merged into master.

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