reqwest ignores `ProxyOverride` parameter on windows

[vegansk]

reqwest doesn't use HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ProxyOverride parameter. If user adds local resources to exceptions list, reqwest will ignore it and will try to use proxy for those resources.

[seanmonstar]

Is this a thing that curl or other client libraries look at? If so, I'd welcome a PR!

[citreae535]

Hi, I've done some research on this issue:

1. curl does not auto-detect windows system proxy, see this to-do item
2. The semantics of ProxyOverride is described here
3. Python's standard library has an implementation for parsing ProxyOverride. But it does not strictly conform to the specifications