Improve the documentation of the implementation of axioms.

[nthiery]

Current documentation: http://sage.math.washington.edu/home/nthiery/sage-6.0/src/doc/output/html/en/reference/categories/sage/categories/category_with_axiom.html

CC: @darijgr @simon-king-jena

Component: categories

Issue created by migration from https://trac.sagemath.org/ticket/15643

[nathanncohen]

comment:1

(looks fun)

[nthiery]

comment:4

Darij: if you have opinions on what should be done in the long run to improve the documentation of axioms, please throw them here!

[nthiery]

Description changed:

--- 
+++ 
@@ -1 +1 @@
-This is a follow up to #10963
+Current documentation: http://sage.math.washington.edu/home/nthiery/sage-6.0/src/doc/output/html/en/reference/categories/sage/categories/category_with_axiom.html