Communicate the Python version on the website (Which is not python 3, its actually python 2)

[mangelozzi]

Python 2 is deprecated, and there are some gotcha when developing regex's with it compared to Python 3. I don't think many people use Python 2 anymore. I recommend adding a 2 after the python to help people not get bit by the same issues I have encountered, something like this:

E.g. this regex from django:

r"""(?P<matched>import(?s:(?P<import>[\s\{].*?))\s*from\s*['"](?P<url>[./].*?)["']\s*;)"""

Is valid in Python3, but this website says it's invalid, leading one to waste so much time trying to figure out the "error"