imply underwater -> water

BUR #6544 has been rejected.

create implication underwater -> water

Self explanatory, saw that there was some mistagged underwater posts that should have water as well.

Previous topic #8028

The water tag is already extremely bloated, not sure if there's any point in keeping underwater apart from it tbh, even the examples in the other thread are debatable.

This bulk update request has been rejected because it was not approved within 45 days.

The bulk update request #6544 (forum #193155) has been rejected by @DanbooruBot.

About this: I don't feel like we should tag this with water.
It's kinda redundant and you technically don't see the water when being underwater (pure physically speaking). It's like tagging air when being on ground.

Agreed with Prov. Underwater is enough, the water wiki explains it well enough.