[analyzer] Document the issue hash debugging facility
[analyzer] Document the issue hash debugging facility

Differential Revision: https://reviews.llvm.org/D39543

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@318030 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 04d07cd0d09a87c4c28f76c592c5b928ad90d325)

apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang