[ASTImporter] Add development internals docs
[ASTImporter] Add development internals docs

Reviewers: a_sidorin, shafik, teemperor, gamesh411, balazske, dkrupp, a.sidorin

Subscribers: rnkovacs, Szelethus, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D66336

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@371839 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang