Move heading for primary menu inside <nav>

[GaryJones]

<nav> is a sectioning element, so to name it, the heading introduced by Leiden should be inside of it, not before it.

The outline for Leiden home page as it stands:

Having it moved inside the <nav> gives:

Since the primary navigation already has a role attribute, supporting ATs can use this to jump directly to it, or the heading, as before.

[rianrietveld]

Hi Gary,

Looked further into this and came up with the following: Moving the H2 for main/secondary navigation inside the

is a good idea.

For a good outline the skip-links should also be placed inside the header and in a

That way it would be given less weight to the HTML5 outline. Also want to add aria-label="skip links" to that nav

This way the outline of an page looks like

[GaryJones]

For a good outline the skip-links should also be placed inside the header

+1. I was a little concerned that a h2 Skip Link was getting bumped to the top of the outline, but was going to address that in a new Issue if it hadn't been caught.

[rianrietveld]

Done in develop branche