polish(zjow): rename 'eval reward' -> 'episode return'

[zjowowen]

fix typo 'eval reward' -> 'episode return'
fix typo 'eval_reward' -> 'episode_return'
fix typo 'EvalReward' -> 'EpisodeReturn'
fix typo 'final eval reward' -> 'eval episode return'
fix typo 'final_eval_reward' -> 'eval_episode_return'
fix typo 'FinalEvalReward' -> 'EvalEpisodeReturn'

[codecov]

Codecov Report

Merging #536 (a6a6766) into main (01b1a8b) will decrease coverage by 0.06%.
The diff coverage is 71.08%.

@@            Coverage Diff             @@
##             main     #536      +/-   ##
==========================================
- Coverage   85.37%   85.31%   -0.07%     
==========================================
  Files         532      532              
  Lines       43943    43869      -74     
==========================================
- Hits        37518    37427      -91     
- Misses       6425     6442      +17     

Flag	Coverage Δ
unittests	85.31% <71.08%> (-0.07%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
ding/entry/serial_entry_gail.py	20.21% <0.00%> (+0.21%)	⬆️
ding/envs/env_manager/envpool_env_manager.py	37.80% <0.00%> (+0.45%)	⬆️
ding/framework/middleware/ckpt_handler.py	96.29% <ø> (ø)
...orker/collector/battle_episode_serial_collector.py	14.28% <0.00%> (+0.08%)	⬆️
...worker/collector/battle_sample_serial_collector.py	13.37% <0.00%> (ø)
ding/worker/collector/metric_serial_evaluator.py	84.69% <ø> (ø)
...orker/coordinator/one_vs_one_parallel_commander.py	98.22% <ø> (ø)
ding/worker/coordinator/solo_parallel_commander.py	0.00% <ø> (ø)
ding/worker/learner/base_learner.py	95.79% <ø> (ø)
ding/envs/env/tests/test_ding_env_wrapper.py	72.80% <50.00%> (+0.77%)	⬆️
... and 79 more

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