improvements to backend documentation

Author: behackl

docs/source/reference/backends.rst

@@ -1,6 +1,11 @@
 Backend Interfaces
 ==================
 
+See :class:`.ACSVSettings` for information on how to
+configure the default computational backends. The module
+:mod:`.sage_acsv.groebner` is the entrypoint for Groebner basis
+computations.
+
 .. toctree::
    :maxdepth: 2
 

sage_acsv/groebner.py

@@ -1,5 +1,14 @@
 """Central interface for accessing and using different backends
 for Groebner basis computations.
+
+Depending on the chosen backend for Groebner basis computations
+(via :meth:`.ACSVSettings.set_default_groebner_backend`, allowed
+values are given in :class:`.ACSVSettings.Groebner`) the members
+of this module delegate their computations to the available
+computational backends:
+
+- :mod:`.backends.default`
+- :mod:`.backends.macaulay2`
 """