docs: fix simple typo, retruns -> returns
There is a small typo in mycroft/skills/skill_data.py.
Should read `returns` rather than `retruns`.
@@ -29,7 +29,7 @@ def read_vocab_file(path):
""" Read voc file.
This reads a .voc file, stripping out empty lines comments and expand
- parentheses. It retruns each line as a list of all expanded
+ parentheses. It returns each line as a list of all expanded
alternatives.
Arguments:
