…ion criterion for buchberger from a maxdegree to max nonzero reductions

…asymptotic linear running time instead of quadratic and replaced the storage of obstructions by a priority queue to remove unnecessary running time there

…lgorithm

AhoCorasickMatches

…AssAlgebraGroebner.jl, also renamed FreeAssAhoCorasick.jl to AhoCorasick.jl

…utomata in the free associative algebra documentation

…om/julien-schanz/AbstractAlgebra.jl into js/nc_groebner_optimization_stable

Not all multivariate polynomial rings can be constructed with
zero indeterminants (e.g. all ring coming from flint).
Thus we always use a generic polynomial ring underpinning the
universal one.

* add `ngens` for `FreeAssAlgebra`

* add `ngens` test for `FreeAssAlgebra`

* Rename poly_ring_type -> dense_poly_ring_type

... for consistency. We can rename it again in the future, but then
together with `dense_poly_type`.

* Add some cross references

There were meant to provide additional generality to maps in Oscar, and
allow writing "more generic" code. In practice, as far as I can tell no
public code outside of AbstractAlgebra ever used them. As to writing
generic code: the idea, as I understand it (which may be wrong) seems to
be that certain generic map implementation can use it to forward
"arbitrary" map functionality, even beyond what they were made for. But
the same could be done by adding explicit forwarding methods, as indeed
this patch does for `domain` and `codomain`. This also means that not
all map types must actually have fields `domain` and `codomain`, as was
the case with the `get_field` mechanism.

They all now accept both rings, ring elements, or their types.
Also fix the docstrings

…asymptotic linear running time instead of quadratic and replaced the storage of obstructions by a priority queue to remove unnecessary running time there

…AssAlgebraGroebner.jl, also renamed FreeAssAhoCorasick.jl to AhoCorasick.jl

…utomata in the free associative algebra documentation

…eeAssAlgebraGroebner.jl

…into js/nc_groebner_optimization_stable

…nd for groebner basis computation while removing redundancies

…he documentation of ObstructionTriple in FreeAssAlgebraGroebner.jl

…om/julien-schanz/AbstractAlgebra.jl into js/nc_groebner_optimization_stable

… for groebner basis computation

…into js/nc_groebner_optimization_stable

…om/julien-schanz/AbstractAlgebra.jl into js/nc_groebner_optimization_stable

…t case for aho corasick automata

… the documentation, also added a documentation for isless in FreeAssAlgebra.jl

…anged some things about the obstruction functions and made the use of Monomial more consistent

…sAlgebraGroebner.jl

…icts

…doctest

…sociative_algebra.md from AbstractAlgebra to AbstractAlgebra.Generic

…type parameters in FreeAssAlgebraGroebner.jl

…e.jl and adding a simple Queue implementation to AhoCorasick.jl