tf_util: spelling / docstring updates
tf_util: spelling / docstring updates

feiwang3311/baseline,openai/baselines,brain-research/mirage-rl-bpttv,hill-a/stable-baselines,openai/baselines,ViktorM/baselines,learnercys/baselines,brain-research/mirage-rl-bpttv,pcchenxi/baseline,peheje/baselines,hill-a/stable-baselines,pcchenxi/baseline,pcchenxi/baseline,pcchenxi/baseline