feat(Mathlib/Analysis/Normed/Module): add instances of CompleteSpace for Submodules and ClosedSubmodule

[yoh-tanimoto]

add an instance of CompleteSpace for a Submodule of a Banach space [NormedField 𝕜] [NormedAddCommGroup E] [NormedSpace 𝕜 E] [CompleteSpace E] which IsClosed.

In this relation, convert a lemma showing IsClosed to an instance for ClosedSubmodule.

motivation: Together with #28709, this makes it automatic that a ClosedSubmodule in a Hilbert space HasOrthogonalProjection.

discussion: https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/.60CompleteSpace.60.20for.20closed.20subtypes.20in.20a.20.60CompleteSpace.60

[github-actions]

PR summary 78c8a8dc7d

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference

---

Declarations diff

+ instance (s : ClosedSubmodule R M) : IsClosed (s : Set M) := s.isClosed'
+ instance [CompleteSpace E] (K : Submodule 𝕜 E) [hc : IsClosed K.carrier] : CompleteSpace K
- isClosed

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.

---

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).

[github-actions]

✅ PR Title Formatted Correctly

The title of this PR has been updated to match our commit style conventions.
Thank you!