Add more comments: 1) EDKII version safe string function is similar as the one C11. 2) If error is returned, the Destination is unmodified. Cc: Michael D Kinney <michael.d.kinney@intel.com> Cc: Liming Gao <liming.gao@intel.com> Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Jiewen Yao <jiewen.yao@intel.com> Reviewed-by: Liming Gao <liming.gao@intel.com>