A description of the rules is missing from the documentation

[ClemensLinnhoff]

Describe the bug

While rules are part of the specification, I could not find any description explaining what the rules mean and how they work in the documentation.

Describe the expected behavior

A dedicated page to explain the rules is needed.

[ClemensLinnhoff]

The rules are briefly mentioned in the contributing section. But still without any description about the rules itself.

There should be a dedicated page about the rules in the main section of the OSI spec, which is linked in the contributing page.