Summary of the new feature / enhancement

As a developer working on cross-platform projects, I often use tools (e.g., GNU Make) that require POSIX-style paths. However, PowerShell's autocomplete function always returns Windows-style paths (with backslashes). For example, when I type make ../o, I would expect it to autocomplete to make ../output/ rather than make ..\output\.

Proposed technical implementation details (optional)

A simple setting that allows users to choose POSIX-style (forward-slash) autocompletion, perhaps configurable in $PROFILE, would be a valuable addition.