next: dimension types are not valid types for static type checking purposes

[DropD]

Problem

from gt4py import next as gtx

KDim = gtx.Dimension("KDim", kind=gtx.DimensionKind.VERTICAL)

@gtx.field_operator
def foo(a: gtx.Field[gtx.Dims[KDim], gtx.int32]) -> gtx.Field[gtx.Dims[KDim], gtx.int32]:
    return a

leads to

error: Variable "KDim" is not valid as a type  [valid-type]

This blocks client projects from type checking stencils effectively.

Proposed Solution

See #2484 for a minimal mypy plugin, which selecively ignores (treats as Any) any type hint with a name ending in "Dim".