[Merged by Bors] - chore(Algebra/QuadraticAlgebra): rename Discr to Discriminant

[xroblot]

Every discriminant file in mathlib spells the word out, RingTheory/Discriminant.lean, Algebra/QuadraticDiscriminant.lean, Algebra/CubicDiscriminant.lean, etc., so QuadraticAlgebra/Discr.lean is renamed to match. The declaration QuadraticAlgebra.discr is unchanged, following Algebra.discr.

Prepared with Claude Code 🤖

[github-actions]

PR summary 405e37b9a2

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference
Mathlib.Algebra.QuadraticAlgebra.Discr	-1372
Mathlib.Algebra.QuadraticAlgebra.Discriminant	1372

---

Declarations diff (regex)

No declarations were harmed in the making of this PR! 🐙

You can run this locally as follows

## from your `mathlib4` directory:
git clone https://github.com/leanprover-community/mathlib-ci.git ../mathlib-ci

## summary with just the declaration names:
../mathlib-ci/scripts/pr_summary/declarations_diff.sh <optional_commit>

## more verbose report:
../mathlib-ci/scripts/pr_summary/declarations_diff.sh long <optional_commit>

The doc-module for scripts/pr_summary/declarations_diff.sh in the mathlib-ci repository contains some details about this script.

Declarations diff (Lean)

✅ Lean-aware diff — post-build, computed from the Lean environment (commit 405e37b).

• +0 new declarations
• −0 removed declarations

No declaration differences.

---

No changes to strong technical debt.

No changes to weak technical debt.

Current commit 405e37b9a2
Reference commit ffbfefaec6

This script lives in the mathlib-ci repository. To run it locally, from your mathlib4 directory:

git clone https://github.com/leanprover-community/mathlib-ci.git ../mathlib-ci
../mathlib-ci/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).

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note: file Mathlib/Algebra/QuadraticAlgebra/Discr.lean` was renamed to `Mathlib/Algebra/QuadraticAlgebra/Discriminant.lean without a module deprecation
Please create a follow-up pull request adding one. Thanks!

[grunweg]

Thanks! Can you split this PR in two - one doing the rename, the other adding the module deprecation? This makes for a much cleaner git diff.

[xroblot]

Done, Sorry about that. This PR is now just the rename, a pure git mv, and the deprecated_module shim is split out into #42976, which depends on this one.

[grunweg]

Thanks!
bors stack #42976

[mathlib-bors]

👎 Cannot stack: #42976 contains this pull request's head, so the stack appears to go the other way. Comment bors stack #42975 on #42976 instead.

[mathlib-bors]

#42976 is now stacked on #42975: both are in a linked bundle and merge in the same batch, or not at all. The batch applies #42975's changes first (#42976's own changes). Each pull request still needs its own bors r+; bors unlink removes the link.

View this bundle in bors (sign in with GitHub to view).

[mathlib-bors]

#42976 is now stacked on #42975: both are in a linked bundle and merge in the same batch, or not at all. The batch applies #42975's changes first (#42976's own changes). Each pull request still needs its own bors r+; bors unlink removes the link.

View this bundle in bors (sign in with GitHub to view).

[grunweg]

Thanks! Now, bors should merge both PRs in the same batch.
bors merge

[mathlib-bors]

🕐 Waiting for approval (bors r+) of: #42976. The bundle enters the queue once every linked pull request is approved.

View this bundle in bors (sign in with GitHub to view).

[mathlib-bors]

Pull request successfully merged into master.

Build succeeded:

• ci (staging) / Test and lint
• ci (staging) / Build
• ci (staging) / Post-Build Step
• ci (staging) / Post-CI job
• ci (staging) / Lint style