Fix azerupi/mdBook#133 by adding a link to the GitHub repo at the end of the --help output.
Fix azerupi/mdBook#133 by adding a link to the GitHub repo at the end of the --help output.

azerupi/mdBook,azerupi/mdBook,petehayes102/mdBook,azerupi/mdBook,superstring/mdBook,superstring/mdBook,petehayes102/mdBook,superstring/mdBook,superstring/mdBook,azerupi/mdBook,petehayes102/mdBook,petehayes102/mdBook