[RFC] Deprecating `highway=road` in Favor of `highway=unknown`

[alan_gr (Alan)]

@julcnx

the reasons to propose the renaming of highway=road to highway=unknown are:

• to include pathways in scope of tag
• to ensure renderers display them in a distinct style (which is not the case)

I don’t think that is really communicated on the proposal page, especially the first point.