If you try to auto-complete "target symbols<TAB>" you get "target symbolsadd"...

If you try to auto-complete "target symbols<TAB>" you get "target symbolsadd" instead of "target symbols ".

Fix this by returning the fact that the "symbols" word is complete if there is nothing else to complete after the "symbols" word.

<rdar://problem/19164599>

llvm-svn: 230408