Add IO::Spec to type-graph.txt

Author: Mouq

type-graph.txt

@@ -119,6 +119,7 @@ class IO::Path::QNX                 is IO::Path
 class IO::ArgFiles                  is IO::Handle
 role  IO::Socket                                   does IO
 class IO::Socket::INET                             does IO::Socket
+class IO::Spec
 
 # Pod
 class Pod::Config