Wrapper function for a coldef. Doesn't do anything that CustomTable wouldn't do naturally when receiving a
CustomColumnSpec, but helps with typing. Typescript doesn't allow an array type of generics to narrow the type
parameters internally. In other words, we won't get proper validation of CellDataType nor ColDataType - i.e. won't
validate that your getter's return type matches your renderer's input type (nor any of the other fields that
involve the cell data type).
Wrapper function for a coldef. Doesn't do anything that CustomTable wouldn't do naturally when receiving a CustomColumnSpec, but helps with typing. Typescript doesn't allow an array type of generics to narrow the type parameters internally. In other words, we won't get proper validation of CellDataType nor ColDataType - i.e. won't validate that your getter's return type matches your renderer's input type (nor any of the other fields that involve the cell data type).