Update hog script parsing to handle `hog.method()` functions

[hholb]

A recent update to groundhog added support for class methods that look like:

import groundhog_hpc as hog

class MyClass:
    @hog.method()
    def say_hello():
        return 'Hello!'

@hog.harness()
def main():
    result = MyClass.say_hello.remote(...)

We need to update the logic in this file to hanlde the new @hog.method decorated functions.