feat(Data/Prod/Lex): WellFoundedRelation (α ×ₗ β)

[vihdzp]

Plus a missing theorem Prod.Lex.left_le

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[github-actions]

PR summary 2bc278b95a

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

+ instance [LT α] [LT β] [WellFoundedLT α] [WellFoundedLT β] : WellFoundedLT (α ×ₗ β)
+ instance [LT α] [LT β] [WellFoundedLT α] [WellFoundedLT β] : WellFoundedRelation (α ×ₗ β)
+ left_le

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.