std.http.Client: add proxy scheme guessing, fix typo

This adds scheme guessing when loading proxies, such that
`HTTP_PROXY=127.0.0.1` and such are valid now and it behaves identically
to `HTTP_PROXY=http://127.0.0.1`. Additionally fixed a typo that was
causing loadDefaultProxies to never populate the https_proxy.
87735e4daeNameless committed on 10/27/2023, 7:42:33 AM· committed by Andrew Kelleyparentda06269
2 files changedLine totals unavailable