BaseTools: update man page to add some descriptions
BaseTools: update man page to add some descriptions

add the description for --ignore-sources and --check-usage into man page.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Yonghong Zhu <yonghong.zhu@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>


git-svn-id: 3158a46dfd52e07d1fda3e32e1ab2e353a00b20f@19144 6f19259b-4bc3-4df7-8a09-765794883524

MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2