os: docs say nothing about path slash types

[bradfitz]

The os package docs say:

Package os provides a platform-independent interface to operating system functionality. The design is Unix-like, although the error handling is Go-like

But nowhere at https://golang.org/pkg/os/ is "slash" mentioned.

Yet there are two Go packages about paths and their slashes: path and path/filepath.

That quoted line above might suggest only forward slashes are permitted ("the design is Unix-like").

Seems like the os package should say what it permits. Users will wonder: forward only? host native only? either way?