ticket:10113: Add snippet tag to dtitvfmt.h, dtptngen.h and plurfmt.h to quote a fragment of the sample code in dtptngsample.cpp, dtitvfmtsample.cpp and plurfmtsample.cpp.

git-svn-id: http://source.icu-project.org/repos/icu/icu/branches/bing@33784 251d0590-4201-4cf1-90de-194747b24ca1