Allow tagged-any & tagged-all to be used in where exprs

This change allows the single tag form of tagged-any &
tagged-all to be used in a where predicate expression.

Previously where-rewrite would only recognize tagged.
The logic for all three forms is the same in this case
because it only checks for the existence of a single tag.

Also update the docs for where, tagged-any & tagged-all to note that tagged-* can be used in where test expressions, but only to test for single tags.