gh-35060: a bijectionist's toolkit

    
We provide a toolkit for the combinatorialist to help find functions
("statistics") s: A -> Z and bijections A -> B given sequences of finite
sets A and B that satisfy various constraints.

Closes #33238

### 📝 Checklist

- [x] I have made sure that the title is self-explanatory and the
description concisely explains the PR.
- [x] I have linked an issue or discussion.
- [x] I have created tests covering the changes.
- [x] I have updated the documentation accordingly.
    
URL: #35060
Reported by: Martin Rubey
Reviewer(s): Martin Rubey, Matthias Köppe, Travis Scrimshaw

src/doc/en/reference/combinat/module_list.rst

@@ -22,6 +22,7 @@ Comprehensive Module List
     sage/combinat/alternating_sign_matrix
     sage/combinat/backtrack
     sage/combinat/baxter_permutations
+    sage/combinat/bijectionist
     sage/combinat/binary_recurrence_sequences
     sage/combinat/binary_tree
     sage/combinat/blob_algebra

src/sage/combinat/all.py

@@ -27,6 +27,7 @@
 - :ref:`sage.combinat.designs.all`
 - :ref:`sage.combinat.posets.all`
 - :ref:`sage.combinat.words`
+- :ref:`sage.combinat.bijectionist`
 
 Utilities
 ---------
@@ -299,3 +300,6 @@
 
 # Path Tableaux
 lazy_import('sage.combinat.path_tableaux', 'catalog', as_='path_tableaux')
+
+# Bijectionist
+lazy_import('sage.combinat.bijectionist', 'Bijectionist')