This approach simplifies the styling needed considerably.
Previously, we had to make room on the left for heading that
are in visual containers. Also we had to apply a `float:right`
when on narrow screens as the gutter not available then.
This float didn't render nicely if the heading text was longer
than could be rendered on a single line.
Closes#22131
Using `display: none` on the `<h1>` causes `innerText` to not work as expected
and include the icon ligature (`link`) in the title. This caused the window
title on the angular.io Home page to appear as "Angular - link".
This commit fixes it by not generating anchors at all for headings with the
`no-anchor` class.
Fixes#20427
PR Close#20440
The autolinking is now done on the `renderedContent` which means it also
captures and autolinks headings that were generated outside of markdown.
PR Close#16336
Pete Bacon Darwin
George Kalpakas