lang: funcs: Make printable function names more unique

This helps a lot with debugging.

lang/funcs/core/fmt/printf_func.go

@@ -62,7 +62,7 @@ type PrintfFunc struct {
 // String returns a simple name for this function. This is needed so this struct
 // can satisfy the pgraph.Vertex interface.
 func (obj *PrintfFunc) String() string {
-	return PrintfFuncName
+	return fmt.Sprintf("%s@%p", PrintfFuncName, obj) // be more unique!
 }
 
 // ArgGen returns the Nth arg name for this function.

lang/funcs/simple/simple.go

@@ -85,7 +85,7 @@ type WrappedFunc struct {
 // String returns a simple name for this function. This is needed so this struct
 // can satisfy the pgraph.Vertex interface.
 func (obj *WrappedFunc) String() string {
-	return obj.Name
+	return fmt.Sprintf("%s@%p", obj.Name, obj) // be more unique!
 }
 
 // ArgGen returns the Nth arg name for this function.

lang/funcs/simplepoly/simplepoly.go

@@ -148,7 +148,7 @@ type WrappedFunc struct {
 // String returns a simple name for this function. This is needed so this struct
 // can satisfy the pgraph.Vertex interface.
 func (obj *WrappedFunc) String() string {
-	return obj.Name
+	return fmt.Sprintf("%s@%p", obj.Name, obj) // be more unique!
 }
 
 // ArgGen returns the Nth arg name for this function.