millisecond time units

[emfdavid]

Describe the bug

milliseconds should be a valid UDUNITS time unit.

ds.coords['time'] error Unrecognized units of measure for time in encoding 'units': 'milliseconds since 1970-01-01T00:00:00 +00:00Z'.] https://bcdev.github.io/xrlint/rule-ref#time-coordinate\time-coordinate]

The _UNAMBIGUOUS_UNITS_OF_TIME list should include ms, us & ns.

To Reproduce
Make Time coordinate with millisecond units. Validate with xrlint("recommened")
See above error report...

Expected behavior
Sub second time units like nanoseconds or ns should be valid.

Python Environment

• operating system: Darwin Mac.fios-router.home 24.6.0 Darwin Kernel Version 24.6.0: Mon Jul 14 11:30:40 PDT 2025; root:xnu-11417.140.69~1/RELEASE_ARM64_T6041 arm64
• XRLint version, output of xrlint --version: xrlint, version 0.5.1
• optional: packages and their versions, output of pip list or conda list:

Additional context
I can open a PR - I think we just need to add to the list of known units?

[forman]

@emfdavid thanks for reporting!

I only had little time lately, so a PR would be much appreciated!