Fix typo in torchscript_freezing.py comment: SciptModule -> ScriptModule (#2323)

Author: evanshrestha

prototype_source/torchscript_freezing.py

@@ -12,7 +12,7 @@
 ------------
 Model freezing can be invoked using API below:
 
- ``torch.jit.freeze(mod : ScriptModule, names : str[]) -> SciptModule``
+ ``torch.jit.freeze(mod : ScriptModule, names : str[]) -> ScriptModule``
 
 Note the input module can either be the result of scripting or tracing.
 See https://pytorch.org/tutorials/beginner/Intro_to_TorchScript_tutorial.html