chore: fix diamonds for Real/Complex Algebra instances

[matthewjasper]

Unfold or make implicit_reducible some definitions used to define Algebra ℝ ℂ . This should allow reducing use of set_option backward.isDefEq.respectTransparency false.

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• depends on: [Merged by Bors] - chore: reduce use of RestrictScalars #36694

[github-actions]

PR summary 5308bb723e

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

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

You can run this locally as follows

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

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

The doc-module for scripts/pr_summary/declarations_diff.sh contains some details about this script.

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Decrease in tech debt: (relative, absolute) = (3.00, 0.00)

Current number	Change	Type
7347	-3	backward.isDefEq

Current commit 22c765ddf9
Reference commit 5308bb723e

You can run this locally as

./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).

[mathlib-merge-conflicts]

This pull request has conflicts, please merge master and resolve them.

[eric-wieser]

I understand why you're doing it, but this change and the one to algebraMap above look fishy; could you split off the less-controversial refactors about RestrictScalars into a pre-work PR so that these changes can be reviewed in isolation?

[mathlib-dependent-issues]

This PR/issue depends on:

• [Merged by Bors] - chore: reduce use of RestrictScalars #36694
  By Dependent Issues (🤖). Happy coding!

[mathlib-merge-conflicts]

This pull request has conflicts, please merge master and resolve them.

[matthewjasper]

closing in favour of #38451