Syntax like

... VECTOR INDEX (column) ...

should be supported in CREATE TABLE, ALTER TABLE, CREATE INDEX.

Note:
First implementation will default to Euclidean distance and HNSW. In the future we can add distance functions / indexing method as part of the:

USING {Euclidean|Cosine Similarity|etc}

ALGORITHM = {HNSW|IVFFLAT|DiskAnn|etc.}

subclause.