Remove focus-visible outline from headings

[susnux]

• Resolves: Focus visible looks funny on headings #2921
• Target version: master

Summary

The focus-visible outline was unintentionally introduced by using a NodeView, but the outline is quite distracting when editing text.

This fixes #2921 by simply removing the outline, but if the outline is now considered to stay, it could be fixed by changing the added rule to look like this:

		/* Fix anchor beeing part of focus ring, #2921 */
		&:focus-visible {
			outline: none;
			[data-node-view-content] {
				outline: 2px auto Highlight;
				outline: 2px auto -webkit-focus-ring-color;
				outline-offset: 4px;
			}
		}

Currently with outline:

With this change and similar to NC24:

[susnux]

/compile