Add Windows path into custom theme docs (#40599)

Closes https://github.com/zed-industries/zed/issues/40584
Closes https://github.com/zed-industries/zed/issues/40057

Release Notes:

- N/A
02b15f0062Kirill Bulatov committed on 10/18/2025, 4:53:19 PM· committed by GitHubparent8d48f9c
1 file changedLine totals unavailable