Social Menu: add regex option to service detection in menu.

[jeherve]

Changes proposed in this Pull Request:

Up until now, social menu items would only rely on host names (e.g. amazon.fr) to detect whether a specific menu item should use a specific icon.
This works well, but isn't very flexible. It's especially problematic for services that typically either have lots of different TLDs, or services that use different domain names.

With this commit, you should now be able to provide either a host name, just like before and ensuring backwards compatibility for folks who have customized that feature on their end, as well as regex for more advanced matching.

In future PRs, I'm hoping to use this new flexibility to add support for more services.

Other information:

• Have you written new tests for your changes, if applicable?
• Have you checked the E2E test CI results, and verified that your changes do not break them?
• Have you tested your changes on WordPress.com, if applicable (if so, you'll see a generated comment below with a script to run)?

Jetpack product discussion

• N/A

Does this pull request change what data or activity we track or use?

• No

Testing instructions:

• Start by switching to an old theme on your site, like Twenty Ten.
• In a functionality plugin, add the following code snippet:

// Add social menu support
add_action( 'after_setup_theme', function () {
	add_theme_support( 'jetpack-social-menu', 'svg' );
} );

• Go to Appearance > Menus, and create a new menu.
• In that menu, add a few custom links pointing to different services supported by Jetpack: Twitter, Strava, ..., and an Amazon link of your choice. Also add an unsupported service, like a link to jetpack.com for example.
• After saving your menu, assign it to the Social Menu location.
• Save your changes.
• Visit the site's frontend and check the look of the menu.

[github-actions]

Thank you for your PR!

When contributing to Jetpack, we have a few suggestions that can help us test and review your patch:

• ✅ Include a description of your PR changes.
  
• ✅ All commits were linted before commit.
  
• ✅ Add a "[Status]" label (In Progress, Needs Team Review, ...).
  
• ✅ Add testing instructions.
  
• ✅ Specify whether this PR includes any changes to data or privacy.
  
• ✅ Add changelog entries to affected projects
  

This comment will be updated as you work on your PR and make changes. If you think that some of those checks are not needed for your PR, please explain why you think so. Thanks for cooperation 🤖

---

The e2e test report can be found here. Please note that it can take a few minutes after the e2e tests checks are complete for the report to be available.

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---

Jetpack plugin:

• Next scheduled release: February 7, 2023.
• Scheduled code freeze: January 30, 2023.

[github-actions]

Are you an Automattician? You can now test your Pull Request on WordPress.com. On your sandbox, run bin/jetpack-downloader test jetpack add/social-menu-add-regex-option to get started. More details: p9dueE-5Nn-p2

[sergeymitr]

Tests well 👍