Update src/sage/homology/homology_vector_space_with_basis.py

Co-authored-by: Travis Scrimshaw <[email protected]>

src/sage/homology/homology_vector_space_with_basis.py

@@ -1279,6 +1279,8 @@ def steenrod_module_map(self, deg_domain, deg_codomain, side='left'):
         - ``side`` default ``'left'``) -- whether we are computing
           the action as a left module action or a right module
 
+        We will write this with respect to the left action;
+        for the right action, just switch all of the the tensors.
         Writing `m` for ``deg_domain`` and `n` for ``deg_codomain``, this
         returns `A^{n-m} \otimes H^{m} \to H^{n}`, one single
         component of the map making `H` into an `A`-module.