Add string representation for AttrsDescriptor

Author: alexbaden

python/triton/backends/compiler.py

@@ -186,6 +186,9 @@ def get_property_key(val, align):
             return "1"
         return "N"
 
+    def __repr__(self):
+        return f"AttrsDescriptor.from_dict({self.arg_properties})"
+
 
 @dataclass(frozen=True)
 class GPUTarget(object):