Update Python comment style

The [PEP8](http://www.python.org/dev/peps/pep-0008/#inline-comments) said:

> An inline comment is a comment on the same line as a statement. Inline
> comments should be separated by at least two spaces from the statement.
> **They should start with a # and a single space**.
Merge branch 'patch-1' of https://github.com/mozillazg/nerdcommenter