[Shell] Environment Variable "DOTFILES" Auto Detection Can't Support Absolute Path

[Johnson9009]

Currently only if the shell initialization file (.zshrc) is a relative link, then the env "DOTFILES" can be set correctly by the logic of file shell/zsh/zshrc because of below code.

dotfiles/shell/zsh/zshrc

Lines 75 to 89 in 88e1a6d

	# Setting the full path of our dotfiles directory automatically.
	# This script can be executed through 3 different ways.
	# - Executed directly by shell through symbolic link(e.g., ~/.zshrc -> zshrc)
	# - sourced by other script through symbolic link(e.g., source ~/.zshrc)
	# - sourced by other script directly(e.g., source zshrc)
	# Below line of code can get the full path of this script no matter how this
	# script is executed.
	SHRC=${(%):-%x}
	# Resolve the real path of this script, if it is a symbolic link.
	while [[ -L ${SHRC} ]]; do
	SHRC=`dirname ${SHRC}`/`readlink ${SHRC}`
	done
	OLD_DIR=`pwd`; cd `dirname ${SHRC}`/../..; unset SHRC
	export DOTFILES=`pwd`
	cd ${OLD_DIR}; unset OLD_DIR