yaourt: support .pkg.tar extension
yaourt: support .pkg.tar extension

pacman's completion already supports this extension so just follow suit.

Motivation: makepkg produces packages (e.g. from AUR) without compression
with its PKGEXT='.pkg.tar' setting, which speeds up building and installing
them manually.

joshuarubin/dotfiles,joshuarubin/dotfiles,joshuarubin/dotfiles,joshuarubin/dotfiles