probability distribution chapter does not seem to open

[leios]

I get the following request error: "GET /contents/probability_distributions/distributions.html) HTTP/1.1" 404 -

[Amaras]

I found the cause of the issue.
The AAA SUMMARY.md file has a trailing space, which is not something that the code had taken into account.
We need to follow Postel's law: "be conservative in what you send, be liberal in what you accept".
I will also open a PR in the AAA to remove the trailing space, in accordance to Postel's law