Run clang-format.

include/yaml-cpp/exceptions.h

include/yaml-cpp/node/convert.h

include/yaml-cpp/node/detail/node_iterator.h

include/yaml-cpp/node/emit.h

src/emit.cpp

src/nodebuilder.cpp

src/null.cpp

src/ptr_vector.h

src/scanner.cpp

test/node/node_test.cpp