clang-format: fix prefix for doxygen comments after member
Summary:
Doxygen supports putting documentation blocks after member, by adding
an additional < marker in the comment block. This patch makes sure
this marker is used in lines which are introduced by breaking the
comment.
int foo; ///< Some very long comment.
becomes:
int foo; ///< Some very long
///< comment.
Contributed by @Typz!
Reviewers: krasimir
Reviewed By: krasimir
Subscribers: djasper, klimek, cfe-commits
Differential Revision: https://reviews.llvm.org/D33282
llvm-svn: 303330