range: clean the deduced transformed type
range: clean the deduced transformed type

wrapping_range and nonwrapping_range offer a transform() member function
which allows creating a new range by applying a transformer function to
the bounds of the current range. The type of bounds of the new range is
deduced from the return type for this transformer function. However the
return type is used as-is, with any CV or reference attached to it.
Since it doesn't make sense to create a range of references or a type
with CV qualifiers strip these off the deduced type.

scylladb/scylla,avikivity/scylla,avikivity/scylla,duarten/scylla,duarten/scylla,scylladb/scylla,avikivity/scylla,duarten/scylla,scylladb/scylla,scylladb/scylla