Move the CheckpointLoaderSimple to the right section.

nodes.py

@@ -213,7 +213,7 @@ class CheckpointLoaderSimple:
     RETURN_TYPES = ("MODEL", "CLIP", "VAE")
     FUNCTION = "load_checkpoint"
 
-    CATEGORY = "_for_testing"
+    CATEGORY = "loaders"
 
     def load_checkpoint(self, ckpt_name, output_vae=True, output_clip=True):
         ckpt_path = os.path.join(self.ckpt_dir, ckpt_name)
@@ -844,6 +844,7 @@ class ImageInvert:
 NODE_CLASS_MAPPINGS = {
     "KSampler": KSampler,
     "CheckpointLoader": CheckpointLoader,
+    "CheckpointLoaderSimple": CheckpointLoaderSimple,
     "CLIPTextEncode": CLIPTextEncode,
     "CLIPSetLastLayer": CLIPSetLastLayer,
     "VAEDecode": VAEDecode,
@@ -872,7 +873,6 @@ NODE_CLASS_MAPPINGS = {
     "DiffControlNetLoader": DiffControlNetLoader,
     "T2IAdapterLoader": T2IAdapterLoader,
     "VAEDecodeTiled": VAEDecodeTiled,
-    "CheckpointLoaderSimple": CheckpointLoaderSimple,
 }
 
 CUSTOM_NODE_PATH = os.path.join(os.path.dirname(os.path.realpath(__file__)), "custom_nodes")