[Merged by Bors] - chore(Data/Option): deprecate Option.iget

[kim-em]

This PR deprecates Option.iget in favor of Option.get! (which will panic on none) or Option.getD (which takes an explicit default value).

See #mathlib4 > `Option.iget` @ 💬

🤖 Prepared with Claude Code

[github-actions]

PR summary 8c8bf56c91

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference

---

Declarations diff

+ getI_eq_getElem?_getD
+ getLastI_eq_getLast?_getD
+ head!_eq_head?_getD
+ option_getD_default
+ surjective_decode_getD

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).

[urkud]

Thanks! Once CI is happy, please merge this PR using bors r+
bors d+

[mathlib-bors]

✌️ kim-em can now approve this pull request. To approve and merge a pull request, simply reply with bors r+. More detailed instructions are available here.

[urkud]

Should we deprecate List.*I from https://leanprover-community.github.io/mathlib4_docs/Mathlib/Data/List/Defs.html too?

[kim-em]

Good idea, but let's do that in a separate PR to keep this one focused.

[kim-em]

bors merge

[mathlib-bors]

Pull request successfully merged into master.

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