chore(cleanup) some non-functional maintenance

- add 'docs' to rockspec for `luarocks doc date` to work
- config trim trailing whitespace
- trim trailing whitespace
- remove test file since it was moved to spec/

.editorconfig

@@ -3,6 +3,7 @@ root = true
 [*]
 end_of_line = lf
 insert_final_newline = true
+trim_trailing_whitespace = true
 charset = utf-8
 
 [*.lua]