Neural-network removal left 9 dangling documentation links

[gabrielfrasantos]

Severity: medium
Domain: docs
Status: VERIFIED — measured against a210d34 on 2026-08-10
Suggested labels: documentation, cleanup

Summary

Commit f4243aa ("feat!: remove neural networks and move to its own repo", #241) deleted
doc/neural_network/, but several surviving documentation pages still link into it. Nine links are
now dead.

Broken links

Source	Dead target
doc/optimization/Optimizer.md	../losses/Loss.md (×2)
doc/optimization/Optimizer.md	../NeuralNetwork.md
doc/optimization/Optimizer.md	../model/Model.md
doc/optimization/Optimizer.md	../../estimators/LinearRegression.md
doc/regularization/Regularization.md	../losses/Loss.md
doc/regularization/Regularization.md	../optimizer/Optimizer.md
doc/regularization/Regularization.md	../../estimators/LinearRegression.md

Confirmed deleted by f4243aa:

doc/neural_network/NeuralNetwork.md
doc/neural_network/losses/Loss.md
doc/neural_network/model/Model.md

Additional pre-existing dead links (same class of problem)

Source	Dead target
doc/filters/active/AhrsMadgwickMahony.md	../ComplementaryFilter.md
doc/filters/active/ExtendedKalmanFilter.md	../../dynamics/EulerLagrange.md
doc/filters/active/KalmanFilter.md	../controllers/Lqr.md (×2), ../solvers/DiscreteAlgebraicRiccatiEquation.md, ../controllers/Pid.md
roadmap/README.md	filters/passive/ExponentialMovingAverage/implementation.md

Note the KalmanFilter.md targets exist but at different relative paths
(../../controllers/Lqr.md), so those are path errors rather than missing content.

Suggested fix

1. Remove or re-point the neural-network references (the content now lives in the extracted repo —
   link to it externally if the cross-reference is still wanted).
2. Correct the relative paths in doc/filters/active/*.
3. Adopt scripts/validate-references.py in CI so the next extraction cannot silently leave dead
   links behind.

Reproduction

python scripts/validate-references.py