In #49105, `where` examples were added to the `normalizes` documentation
to demonstrate that normalizations are also applied for `where`.
However, as with the `exists?` examples, we should also demonstrate that
normalizations are only applied to keyword arguments, not positional
arguments.  We can also address the original source of the confusion by
changing the wording of "finder methods" to "query methods".

This commit also removes the tests added in #49105.  `normalizes` works
at the level of attribute types, so there is no need to test every query
method.  Testing `find_by` is sufficient.  (And, in point of fact,
`find_by` is implemented in terms of `where`.)