Add `backend` option to associahedron and flow polytope

[kliem]

The option backend was missing for polytopes.associahedron and polytopes.flow_polytope.

CC: @jplab

Component: geometry

Keywords: polytopes, associahedron, flow polytopes, backend, normaliz

Author: Jonathan Kliem

Branch/Commit: e137199

Reviewer: Jean-Philippe Labbé, Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/27798

[kliem]

New commits:

2643078

added `backend` to associahedron and flow polytope

[kliem]

Branch: public/27798

[kliem]

Commit: 2643078

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

a9b4826

typo

[sagetrac-git]

Changed commit from 2643078 to a9b4826

[seblabbe]

comment:3

The doc should include in the description of backend input of both functions:

If ``None`` then ``backend='ppl'`` is used.

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

8716985

corrected docstring

[sagetrac-git]

Changed commit from a9b4826 to 8716985

[kliem]

Author: Jonathan Kliem

[kliem]

Changed keywords from none to polytopes, associahedron, flow polytopes, backend, normaliz

[kliem]

Description changed:

--- 
+++ 
@@ -1 +1 @@
-The option `backend` was missing for `polytopes.associahedron` and `polytopes.flow_polytopes`.
+The option `backend` was missing for `polytopes.associahedron` and `polytopes.flow_polytope`.