Make ILayoutRestorer optional in the extension tutorial

[jtpio]

References

Fixes #11611.

The motivation here is to make extension authors more aware of the optional field of the plugin definition, so they can build extensions that can be used in more JupyterLab based applications by default.

Code changes

Documentation changes.

• Make ILayoutRestorer an optional to cover optional in the extension tutorial
• Keep ICommandPaletter as requires to also cover tokens specified as requires.

User-facing changes

None for end users.

Documentation changes can be previewed on RTD: https://jupyterlab--11677.org.readthedocs.build/en/11677/extension/extension_tutorial.html

Backwards-incompatible changes

None

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[jtpio]

A follow-up to this would be to update the apod repo to take these changes into account: https://github.com/jupyterlab/jupyterlab_apod

[fcollonval]

Thanks @jtpio

I caught a typo. Otherwise LGTM

[fcollonval]

LGTM

[github-actions]

Benchmark report

The execution time (in milliseconds) are grouped by test file, test type and browser.
For each case, the following values are computed: min <- [1st quartile - median - 3rd quartile] -> max.

The mean relative comparison is computed with 95% confidence.

Results table

Test file	large_code_notebook	large_md_notebook
open
chromium
actual	5447 <- [5612 - 5665 - 5690] -> 5938	3687 <- [3754 - 3796 - 3833] -> 3965
expected	5439 <- [5558 - 5593 - 5654] -> 5896	3662 <- [3728 - 3764 - 3802] -> 4018
Mean relative change	0.9% ± 0.4%	0.7% ± 0.4%
switch-from
chromium
actual	676 <- [747 - 774 - 848] -> 1140	555 <- [584 - 599 - 617] -> 845
expected	676 <- [746 - 781 - 1000] -> 1121	561 <- [587 - 600 - 613] -> 640
Mean relative change	-2.6% ± 4.2%	0.8% ± 1.4%
switch-to
chromium
actual	389 <- [443 - 452 - 467] -> 494	320 <- [368 - 377 - 381] -> 409
expected	385 <- [442 - 452 - 469] -> 509	316 <- [365 - 374 - 384] -> 427
Mean relative change	0.1% ± 1.5%	0.6% ± 1.2%
close
chromium
actual	735 <- [817 - 838 - 1231] -> 1370	562 <- [601 - 611 - 623] -> 650
expected	748 <- [805 - 837 - 1220] -> 1299	564 <- [597 - 609 - 623] -> 672
Mean relative change	-0.6% ± 5.9%	0.3% ± 0.8%

Changes are computed with expected as reference.

[fcollonval]

I think we should wait to solve jupyterlab/jupyterlab_apod#10 before backporting it to 3.2.x