Fix the dimension of PolyhedronFace

[LaisRast]

In this ticket, I am going to fix the implementation of the method dim of PolyhedronFace. This problem occurs when we have a vertex and a ray (or a line) with the same vector.
See the following example.

sage: P = Polyhedron(vertices=[[1,0]], rays=[[1,0],[0,1]]); P
A 2-dimensional polyhedron in QQ^2 defined as the convex hull of 1 vertex and 2 rays
sage: P.faces(P.dim())[0]
A 1-dimensional face of a Polyhedron in QQ^2 defined as the convex hull of 1 vertex and 2 rays

CC: @jplab @kliem

Component: geometry

Keywords: polytopes, polyhedronface, dimension

Author: Laith Rastanawi

Branch/Commit: 67d3ce0

Reviewer: Jonathan Kliem

Issue created by migration from https://trac.sagemath.org/ticket/28650

[LaisRast]

Commit: 4e5912d

[LaisRast]

New commits:

4e5912d

fix PolyhedronFace.dim()

[LaisRast]

Branch: public/28650

[LaisRast]

Author: Laith Rastanawi

[sagetrac-git]

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

ae40381

code within 79 columns

[sagetrac-git]

Changed commit from 4e5912d to ae40381

[kliem]

comment:3

Missing a doctest, which shows that the bug is fixed.

[sagetrac-git]

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

632a2d9

add a test in the docstring