This small S3 class provides methods for [ and c() and ensures
the following invariants:
The list only contains quosures.
It is always named, possibly with a vector of empty strings.
new_quosures() takes a list of quosures and adds the quosures
class and a vector of empty names if needed. as_quosures() calls
as_quosure() on all elements before creating the quosures
object.
Arguments
- x
 A list of quosures or objects to coerce to quosures.
- env
 The default environment for the new quosures.
- named
 Whether to name the list with
quos_auto_name().
