given that implementor classes always use  arg as object, cannot actually accept a string arg
fix bug due to duplicate FileDescriptor existence;
these classes seem to echo those in phpDoc\Descriptor, so set @param to more tightly match them;
go ahead and typehint on DescriptorAbstract on the interface and these UrlGenerator children;
param tags should show DescriptorAbstract to match method signature;
some Original* use statements become unnecessary afterward;
use more direct namespace alias
string args are a use case, so no typehints
restore more specific parameter typehints
Merge pull request #1071 from ashnazg/fix-build

Fix the FileDescriptor Fatals in the build