Add <ESC> key xterm info to FAQ
Add <ESC> key xterm info to FAQ

This is fruit of an email exchange I had with a user; he suggested
adding this to the docs.

Signed-off-by: Greg Hurrell <79e2475f81a6317276bf7cbb3958b20d289b78df@hurrell.net>

mtimkovich/command-t,wincent/command-t,supriyantomaftuh/command-t,yrro/command-t,simichaels/dotfiles,supriyantomaftuh/command-t,yrro/command-t,lencioni/command-t,besarthoxhaj/command-t,vrkansagara/command-t,vrkansagara/command-t,1234-/command-t,lencioni/command-t,mtimkovich/command-t,1234-/command-t,simichaels/dotfiles,besarthoxhaj/command-t,wincent/command-t,wincent/command-t