data loading typo

[quantumiracle]

Hi, this line should be:

assert self.buffer.num_eps == (self.buffer.capacity // _cfg.episode_length), \
	f'Buffer has {self.buffer.num_eps} episodes, expected {self.buffer.capacity // _cfg.episode_length} episodes.'

[nicklashansen]

Great catch! This seems to be a leftover from the previous buffer implementation (pre commit 54145a4). I'll fix this soon and double-check that everything else in the offline trainer works as expected.