Recommend addingwater= tag to natural=water areas

[jeisenbe]

Please consider adding a validation rule which checks for natural=water areas which lack a water= tag.

As mentioned in #6853 (comment) and #6853 (comment) there are a large and growing number of natural=water areas which lack a water=* tag, such as water=lake, water=river, etc.

This makes it difficult to analyze, search for, and render different water areas, like river areas vs lakes vs canals. (It's not possible to select all natural=water area which contain a waterway=river line, because these can enter reservoirs, lakes, and coastal marine waters.)

[quincylvania]

@jeisenbe Thanks for the suggestion. We could do this once we do #6101.