Markdown: break ties in table of contents

C++ and C# both hashed to the same "C_" token in the table of
contents. Break these kinds of ties by giving "C_" to the first
and "C_-$hash(C++)" to the second.

Change-Id: Ib568d2ab92a3a78b846ff6ad41ba4d754b8d48cc
1 file changed