[clang-doc] Add second index for sections within info's content
This new index contains links to the main section of infos: Namespaces, Records, Functions, Enums, Members.
Also to each child function or enum.
Index is currently rendered on top of the info content, this will be fixed later with CSS.
Depends on D65690.
Differential Revision: https://reviews.llvm.org/D65030
git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@368209 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed
