adding uninstall to the docs

[nicklm0]

Hi sir I'm interested contributing on the oh-my-posh project i would like to add uninstall on the oh-my-posh docs using winget for some folks who don't know how to uninstall

[JanDeDobbeleer]

@nickaldwin uninstalling isn't something that should be added to our docs imho, that's a package manager docs context.