feat(RingTheory/Polynomial): some lemmas about Ideal.leadingCoeff

[mbkybky]

Add some lemmas about Ideal.leadingCoeff.

---

[github-actions]

PR summary 56e100aabd

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference

---

Declarations diff

+ leadingCoeff_finset_prod_le
+ leadingCoeff_mono
+ leadingCoeff_mul_le
+ leadingCoeff_pow_le
+ leadingCoeff_top
+ map_C_comap_of_comap_eq_leadingCoeff
+ map_C_leadingCoeff

You can run this locally as follows

## summary with just the declaration names:
./scripts/pr_summary/declarations_diff.sh <optional_commit>

## more verbose report:
./scripts/pr_summary/declarations_diff.sh long <optional_commit>

The doc-module for scripts/pr_summary/declarations_diff.sh contains some details about this script.

---

No changes to technical debt.

You can run this locally as

./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).

[github-actions]

✅ PR Title Formatted Correctly

The title of this PR has been updated to match our commit style conventions.
Thank you!

[wwylele]

Suggested change

	lemma leadingCoeff_mono {I J : Ideal R[X]} (hIJ : I ≤ J) : I.leadingCoeff ≤ J.leadingCoeff := by
	@[gcongr]
	lemma leadingCoeff_mono {I J : Ideal R[X]} (hIJ : I ≤ J) : I.leadingCoeff ≤ J.leadingCoeff := by