chore: no noncomputable inside noncomputable section

[felixpernegger]

This PR removes all redundant noncomputable def etc when we are already inside a noncomputable section.

---

[mathlib-bors]

This pull request is now in draft mode. No active bors state needed cleanup.

While this PR remains draft, bors will ignore commands on this PR. Mark it ready for review before using commands like bors r+ or bors try.

[github-actions]

PR summary a58c317e71

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 (regex)

-+-+ Forget₂.createsLimit
-+-+ abelian
-+-+ forget_createsLimits
-+-+ forget₂Mon_preservesFilteredColimits
-+-+ instance (U : (Opens (TopCat.of M))ᵒᵖ) :
-+-+ isColimitLocallyConstantPresheaf
-+-+ limitConeIsLimit
-+-+ mapPiLocalization
-+-+ objAsTypeEquiv
-+-+-+ colimitCoconeIsColimit
-+-+-+ forget_createsLimitsOfShape
-+-+-+ forget_preservesFilteredColimits
-+-+-+-+ colimitCocone
-+-+-+-+ forget_createsLimit
-+-+-+-+ forget_createsLimitsOfSize
-+-+-+-+ limitCone

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 -- unavailable)

⚠️ The Mathlib cache for this PR's merge-base isn't on the server (typically a bors-batch intermediate that CI never built). Merge master into this PR and push to refresh.

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No changes to strong technical debt.

No changes to weak technical debt.

Current commit a58c317e71
Reference commit e3b73828b0

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).

[felixpernegger]

!bench

[leanprover-radar]

Benchmark results for a58c317 against e3b7382 are in. No significant results found. @felixpernegger

• 🟥 build//instructions: +104.3G (+0.07%)

No significant changes detected.

[mathlib-bors]

This pull request is now in draft mode. No active bors state needed cleanup.

While this PR remains draft, bors will ignore commands on this PR. Mark it ready for review before using commands like bors r+ or bors try.