tests: Add a regression test for issue #392 (aliases beginning with a '+' are lost).
tests: Add a regression test for issue #392 (aliases beginning with a '+' are lost).

x-way/zsh-syntax-highlighting,zsh-users/zsh-syntax-highlighting,joshuarubin/dotfiles,P71/zsh-syntax-highlighting,danielshahaf/zsh-syntax-highlighting,P71/zsh-syntax-highlighting,stuha/wbr-zsh,zsh-users/zsh-syntax-highlighting,joshuarubin/dotfiles,phy1729/zsh-syntax-highlighting,danielshahaf/zsh-syntax-highlighting,x-way/zsh-syntax-highlighting,joshuarubin/dotfiles,joshuarubin/dotfiles,phy1729/zsh-syntax-highlighting