feat(Algebra/Order): add MulLeftMono implies IsDedekindFinite instance

[NoahW314]

In the process, generalize an existing lemma that required both MulLeftMono and MulRightMono into two lemmas that only require one of MulLeftMono or MulRightMono.

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[github-actions]

PR summary 08b44d8fef

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 (regex)

+ mul_eq_one_iff_of_one_le_left
+ mul_eq_one_iff_of_one_le_right
++ instance (priority := 100) [IsBotOneClass α] : IsDedekindFiniteMonoid α

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 -- pending)

Computed after the build finishes.

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No changes to strong technical debt.

Increase in weak tech debt: (relative, absolute) = (1.00, 0.12)

Current number	Change	Type (weak)
8	1	large files

Current commit 08b44d8fef
Reference commit 79f249234c

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).