chore(AlgebraicGeometry/Sites): use Precoverage.toGrothendieck instead of Pretopology.toGrothendieck

[chrisflav]

As more and more API is developed in terms of Precoverages and Precoverage.toGrothendieck, this makes application of the general category theory library easier.

We also add a few additional API lemmas.

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[github-actions]

PR summary 85028a69f0

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

+ bot_mem_grothendieckTopology
+ bot_mem_precoverage
+ etalePrecoverage
+ precoverage_mono

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).