docs: "clang tools" are not a different interface.

I spotted someone confused about this, so remove the heading to make it
clear that they really are a part of Tooling.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@171841 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed