feat: use a constructor for NNReal

[sgouezel]

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[github-actions]

PR summary cd8272a9d5

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

+ Measurable.nnreal_mk
+ inv_mk
+ mk
+-+--+ nnnorm_nnratCast

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.

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Decrease in tech debt: (relative, absolute) = (2.00, 0.00)

Current number	Change	Type
6899	-2	backward.isDefEq.respectTransparency

Current commit 4700e96569
Reference commit cd8272a9d5

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).