Update CommandLine.rst getRegisteredOptions example

Summary: Update the docs to match the changes in http://reviews.llvm.org/D7132

Reviewers: beanz, llvm-commits, modocache

Differential Revision: https://reviews.llvm.org/D26296

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286094 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed