[Merged by Bors] - feat(Geometry/Euclidean/Angle): angles with orthogonal projections

[jsm28]

Add some lemmas that angles involving orthogonal projections are right angles. The unoriented versions abstract something used multiple times in Mathlib.Geometry.Euclidean.Angle.Bisector (which is thus refactored to use the new lemmas); I expect the oriented versions may be of use in future in further oriented angle bisection lemmas building on top of #30477.

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[github-actions]

PR summary 57f5895e92

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference
Mathlib.Geometry.Euclidean.Angle.Bisector	1
Mathlib.Geometry.Euclidean.Angle.Unoriented.Projection (new file)	2065
Mathlib.Geometry.Euclidean.Angle.Oriented.Projection (new file)	2131

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Declarations diff

+ angle_orthogonalProjection_self
+ angle_self_orthogonalProjection
+ oangle_orthogonalProjection_self
+ oangle_self_orthogonalProjection
+ two_zsmul_oangle_orthogonalProjection_self
+ two_zsmul_oangle_self_orthogonalProjection

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).

[jcommelin]

Thanks 🎉

bors merge

[mathlib-bors]

Pull request successfully merged into master.

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