Star and acyclic coloring -- enhanced edition (#214)

* Star and acyclic coloring -- enhanced edition

* Create a function build_edge_to_index

* Backport the modifications of Guillaume

* Fix the tests in order.jl

* Fix the code coverage

* Update bidirectional_pattern

* Avoid leaking memory between structs

* Fix

---------

Co-authored-by: Guillaume Dalle <22795598+gdalle@users.noreply.github.com>

Author: amontoison

docs/src/dev.md

@@ -23,7 +23,6 @@ SparseMatrixColorings.bidirectional_pattern
 
 ```@docs
 SparseMatrixColorings.partial_distance2_coloring
-SparseMatrixColorings.symmetric_coefficient
 SparseMatrixColorings.star_coloring
 SparseMatrixColorings.acyclic_coloring
 SparseMatrixColorings.group_by_color