Update jQuery v3.6.3 to v3.6.4

[TobiasBg]

​Version 3.6.4 of jQuery has been released.

This release is an improvement release. The jQuery team does not expect other compatibility issues when upgrading from a jQuery 3.0+ version.

A full list of changes in this release can be found on GitHub: ​https://github.com/jquery/jquery/compare/3.6.3...3.6.4.

For updating the jQuery version in WordPress, package.json and script-loader.php need to get the new version string.

Related: #57324, #56451, #52707, #51812, #50564, #37110.

[jorbin]

I think this is something we should do for 6.2 since it's a small change and we already updated jQuery in 6.2. I don't see a lot of value in waiting until 6.3.

Barring objection, I can do this later today

Tagging @hellofromTonya and @audrasjb as core tech leads in case they have an objection.

[audrasjb]

Thanks for the ping! Looking at the changeset/diff right now 👀

[hellofromTonya]

Hmm, the last Beta has already happened and RC1 is tomorrow. A change like this right before RC1 makes me nervous.

But .. let's look at what's in this version to determine if there any risks to the release.

This version includes 2 changes:

• The first change is for build process on Windows.
• The second change ​fixes errors in Firefox:

  Uncaught Error: Syntax error, unrecognized expression: unsupported pseudo: before
  

The 2nd change is in the ​Sizzle CSS Selector Engine to "mostly" rollback to a previous try-catch:

From ​https://github.com/jquery/jquery/pull/5206:

Taking all that into account, we go back to our previous try-catch approach without relying on CSS.supports( "selector(...)" ). The only difference is we detect forgiving parsing in :has() and mark the selector as buggy.

Reasonings are shared in ​the release post.

So I think this upgrade is needed to avoid similar issues in Firefox. I think it's low risk to commit it for RC1. It shouldn't need a beta either.

@audrasjb what do you think?

[audrasjb]

I took a look at the ​release post and the full ​changeset and it looks like a minor update to fix issues occurring with Firefox. IMO, cross-browser compatibility is actually the main interest in using a library like jQuery, so I'd say that it's worth having this in 6.2. Plus, it looks pretty straightforward.

I think the best thing to do is to commit this now/asap so we have still 24h to revert it before WP 6.2 RC 1 —and we can even revert it later— if anything goes wrong.

Reassigning to @jorbin for commit.
(I'm available to commit it today if needed, feel free to reassign)

[jorbin]

Fixed in https://core.trac.wordpress.org/changeset/55491 (forgot the #)

Thanks Y'all.