docs: packages/umfpack-jax.md says Windows is 'Not yet supported' but CI now builds Windows wheels

[github-actions]

Problem

docs/packages/umfpack-jax.md has the following platform support table:

Platform	Architecture	Status
Linux	x86_64	Supported
Linux	aarch64	Supported
macOS	arm64	Supported
Windows	x86_64	Not yet supported

However, commit 6dbf669 ("ci: Enable umfpack-jax Windows wheel builds") explicitly adds Windows to the CI build matrix in release.yml, with vcpkg OpenBLAS integration. This makes the "Not yet supported" status stale.

Fix

Update the table to reflect that Windows x86_64 is now in progress / supported as of that commit.