Naming the dtypes from zarr-python#2874

[jhamman]

zarr-developers/zarr-python#2874 is proposing to add a number of new extension datatypes to Zarr-Python. Currently, @d-v-b has named prefixed the dtypes in that PR with numpy.. This issue proposes removing the numpy prefix. Below

Dtype Class	Current name in zarr-developers/zarr-python#2874	Proposed dtype extension name
FixedLengthAscii	numpy.fixed_length_ascii	fixed-length-ascii
FixedLengthBytes	numpy.void	fixed-length-bytes
FixedLengthUnicode	numpy.fixed_length_ucs4	fixed-length-ucs4
DateTime64	numpy.datetime64	datetime64

Notes:

• The PR also includes a Structured Dtype that I am intentionally leaving out of this issue to keep the scope manageable.
• adds extensions that zarr-python defines #1 adds the variable length string and bytes dtypes already implemented in Zarr-Python 3

Questions:

• is there anything wrong with the proposed names? I'd love to avoid bike shedding on possible names here.
• Noting that adds extensions that zarr-python defines #1 has not merged despite being open for some time, is this issue sufficient for moving ahead with refactor v3 data types zarr-python#2874?

cc: @d-v-b, @normanrz, @rabernat

[d-v-b]

we should also consider the configuration for these data types.

• the fixed-length data types must all be parametrized by their length in bytes (or bits)
• the datetime64 dtype is parametrized by the unit, which is a string defined here

[normanrz]

I think the names are ok. The spec documents should definitely contain the configuration params. The spec doc should also contain information about how these dtypes can be (de)serialized, i.e. what array-bytes codecs supports them and how.

[mkitti]

Why is - used in the extension name rather than underscore _ here?