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

Author: chisophugis

docs/Tooling.rst

@@ -82,9 +82,6 @@ Do not use LibTooling when you...:
 * want high level abstractions like cursors and code completion out of the box
 * do not want to write your tools in C++
 
-Clang Tools
------------
-
 :doc:`Clang tools <ClangTools>` are a collection of specific developer tools
 built on top of the LibTooling infrastructure as part of the Clang project.
 They are targeted at automating and improving core development activities of