[Merged by Bors] - feat: a convex set is closed under betweenness

[YaelDillies]

From LeanCamCombi

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[github-actions]

PR summary c94430c89a

Import changes for modified files

Dependency changes

File	Base Count	Head Count	Change
Mathlib.Analysis.Convex.Between	1198	1203	+5 (+0.42%)

Import changes for all files

Files	Import difference
Mathlib.Analysis.Convex.Between	5

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Declarations diff

+ AffineSubspace.mem_of_wbtw
+ AffineSubspace.right_mem_of_wbtw
+ Convex.mem_of_wbtw
+ Wbtw.mem_segment
+ _

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.

[ADedecker]

Thanks!

bors merge

[mathlib-bors]

Pull request successfully merged into master.

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