Wrong class imported for SQLAlchemy

[tux-type]

This example does not work for SparseVector and HalfVector:

from pgvector.sqlalchemy import Vector

class Item(Base):
    embedding = mapped_column(Vector(3))

When importing using:

from pgvector.sqlalchemy import Vector, SparseVector, HalfVector

Vector is correctly imported as UserDefinedType VECTOR, but SparseVector, and HalfVector are not.

pgvector-python/pgvector/sqlalchemy/__init__.py

Lines 1 to 8 in 57b6a61

	from .bit import BIT
	from .functions import avg, sum
	from .halfvec import HALFVEC
	from .sparsevec import SPARSEVEC
	from .vector import VECTOR
	from .vector import VECTOR as Vector
	from ..utils import HalfVector, SparseVector

[ankane]

Hi @tux-type, see the docs for the right types to import for SQLAlchemy.