Fixes nullability fix-it for `id<SomeProtocol>`. With this change
nullability specifier is inserted after ">" instead of between
"id" and "<".
rdar://problem/34260995
Reviewers: jordan_rose, doug.gregor, ahatanak, arphaman
Reviewed By: jordan_rose
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D38327
llvm-svn: 314473