docs: ZippedHTML link is dead

[AlexHenderson]

Hi,

On your docs homepage https://zarr.readthedocs.io/en/stable/index.html the "Download documentation: [Zipped HTML]"(https://zarr.readthedocs.io/_/downloads/en/stable/htmlzip/) link is dead.

Thanks,
Alex

[sanketverma1704]

Hi @AlexHenderson.

Thanks for spotting it. I've fixed it now.
Should be visible in the next release soon.