Update LinkControl docs with advice to memoize value prop

[getdave]

What?

Documents the best practice to memoize the value prop passed to <LinkControl>.

Addresses #54603 (comment)

Props to @Mamaduka for the inspiration and the great work to fix this Issue in Core.

Why?

LinkControl is likely to be inside other compomnents which may re-render. If value is not-memozied then LinkControl will then also have to re-render.

As LinkControl maintains it's own internal state of any changes made by the user interacting with the control prior to submitting their changes. This is synchronised with the value prop passed to the component.

By memoizing the value we avoid this.

This pattern is established in Core PRs:

• Formats: Memoize link value passed to the LinkControl #54603
• Button: Memoize link value passed to the LinkControl #53507

How?

Add documentation.

Why don't you just remove the internal state?

If you ask this question please carefully read and evaluate the discussion in #51387 🙇

Testing Instructions

• Check that documentation is accurate.
• Check that the wording makes sense.
• Check that it marries with approach in the referenced PRs

Testing Instructions for Keyboard

Screenshots or screencast

[github-actions]

Flaky tests detected in 6fb2d75.
Some tests passed with failed attempts. The failures may not be related to this commit but are still reported for visibility. See the documentation for more information.

🔍 Workflow run URL: https://github.com/WordPress/gutenberg/actions/runs/6406030158
📝 Reported issues:

• [Flaky Test] should partially select with shift + click (@webkit) #53524 in /test/e2e/specs/editor/various/multi-block-selection.spec.js

[Mamaduka]

Thank you, @getdave!