code: public static Tag newTag(String prefix, String name) {
          return newTag(newSymbol(prefix, name));
      }
docs: Provide a Tag with the given prefix and name.
  <p>
  Bear in mind that tags with no prefix are reserved for use by the edn
  format itself.
  
  @param prefix
  An empty String or a non-empty String obeying the restrictions
  specified by edn. Never null.
  @param name
  A non-empty string obeying the restrictions specified by edn.
  Never null.
  @return a Keyword, never null.