[clang-tidy] Fix the YAML created for checks like modernize-pass-by-value

[clang-tidy] Fix the YAML created for checks like modernize-pass-by-value

Currently this check generates the replacement with the newline in the end.
The proper way to export it to YAML is to have two \n\n instead of one.
Without this fix clients should reinterpret the replacement as
"#include <utility> " instead of "#include <utility>\n"

Differential Revision: https://reviews.llvm.org/D63482

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@365017 91177308-0d34-0410-b5e6-96231b3b80d8