code: protected DocPath pathString(PackageDoc pd, DocPath name) {
          return pathToRoot.resolve(DocPath.forPackage(pd).resolve(name));
      }
docs: Return path to the given file name in the given package. So if the name
  passed is "Object.html" and the name of the package is "java.lang", and
  if the relative path is "../.." then returned string will be
  "../../java/lang/Object.html"
  
  @param pd Package in which the file name is assumed to be.
  @param name File name, to which path string is.