feat(jump-links)!: reimplement in line with PFv4

[bennypowers]

What I did

• added @patternfly/pfe-core/controllers/scroll-spy-controller.js
• reimplemented pfe-jump-links with above, and with styles and APIs in line with PFv4 designs

Testing Instructions

Run the demo locally, and check the Deploy Preview

• is it accessible?
• how quickly can you break the scroll spy? under what conditions? give clear repros, please!
• compare the styles and behaviour to PFv4 and to the Scroll spy demo (Deploy Preview)

Notes to reviewers

Public APIs/HTML

Keep in mind that the primary goal here is to replicate the pfv4 dx, not to provide a strictly html-first element. Nonetheless, the controller tries not to presume anything about the available DOM, so that it could be useful in implementing a light-dom-heavy version of jump-links in the near future (i.e. rh-jump-links or rh-table-of-contents, whathaveyou).

Try to think ahead to what you'd need to implement an HTML-first / noscript-y version of this, and think if the controller as-is would be enough.

Assumptions made

There are, as far as i can tell, two places where the controller makes assumptions about it's host's light DOM, both regarding this concept of "link children". Link children are the elements in the controller host's light-dom which link to the scrollable content headings. when the content scrolls up and down the page, the link child which represents the current heading should become "active".

1. we assume that link children have an href attribute which contains a hash reference to its heading (i.e. <a href="#foo"> or <pfe-jump-links-item href="#bar">
2. we assume that it's sufficient to toggle some attribute on the link child when its heading scrolls into view.

If you find these assumptions to be too restrictive, please speak up.

[changeset-bot]

🦋 Changeset detected

Latest commit: 434527d

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@patternfly/pfe-jump-links	Major
@patternfly/pfe-core	Minor

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[github-actions]

✅ Deploy Preview for patternfly-elements ready!

Name	Link
🔨 Latest commit	e838dbf
😎 Deploy Preview	https://deploy-preview-2283--patternfly-elements.netlify.app/

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[bennypowers]

Thanks @nikkimk ! This should probably get a changeset for adding roving tabindex controller

[brianferry]

For the scrollspy demo locally I am not able to navigate with my keyboard to any of the headings other than 1 & 5 (first and last) using the arrow keys. Not sure if that is expected or not but didn't see a disabled attribute on those elements.

[zeroedin]

For the scrollspy demo locally I am not able to navigate with my keyboard to any of the headings other than 1 & 5 (first and last) using the arrow keys. Not sure if that is expected or not but didn't see a disabled attribute on those elements.

Not sure what you are seeing @brianferry but FWIW I am able to navigate fine with the arrows, home, and end key all working as expected.

[zeroedin]

LGTM