zsh-syntax-highlighting

To activate the syntax highlighting, add the following at the end of your .zshrc:
  source $HOMEBREW_PREFIX/share/zsh-syntax-highlighting/zsh-syntax-highlighting.zsh

If you receive "highlighters directory not found" error message,
you may need to add the following to your .zshenv:
  export ZSH_HIGHLIGHT_HIGHLIGHTERS_DIR=$HOMEBREW_PREFIX/share/zsh-syntax-highlighting/highlighters