Define navigation in Important Terms

[chlane]

I think defining navigation in the Important Terms section of the spec will be helpful. The definition should mention routing. Doing this would support the resolution of #1353. A link to the definition of navigation will be useful in the link role as well.

[jnurthen]

Discussed on call - we will not define in ARIA but link to a definition elsewhere

[carmacleod]

Possibly https://html.spec.whatwg.org/multipage/history.html#history

[jnurthen]

closing this. If we need a definition when fixing a different issue we can create the term then. I don't propose creating terms without a substantive use.