Update "Specifying a uniform font size for h1"

[zcorpan]

See whatwg/html#11102

Description

Update wording to reflect that the spec has been changed.

Motivation

Preparing to land the spec change. (This can be merged after the spec change has landed.)

Additional details

Related issues and pull requests

[github-actions]

Preview URLs

• /en-US/docs/Web/HTML/Reference/Elements/Heading_Elements

External URLs (2)

URL: /en-US/docs/Web/HTML/Reference/Elements/Heading_Elements
Title: <h1>–<h6>: The HTML Section Heading elements

• https://github.com/whatwg/html/issues/7867 (1 time) (Note! This may be a new URL 👀)
• https://html.spec.whatwg.org/multipage/rendering.html (1 time) (Note! This may be a new URL 👀)

[chrisdavidmills]

@zcorpan usually, we don't like putting time-dependent information in MDN content. But in this case, I don't see a better way of conveying what has happened.

I do think we should add a data point to the BCD to show what browsers have made this change, and when, otherwise people reading "browsers that implement the old context-dependent default style" might think "well, which browsers need this?"