gh-37260: extend `all_paths_iterator` and `all_simple_paths` to Graph
This answer a question from
https://ask.sagemath.org/question/75715/all_simple_paths-generates-
attributeerror-for-graphs/
We make methods `all_paths_iterator` and `all_simple_paths` work for
both `Graph` and `DiGraph`.
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URL: https://github.com/sagemath/sage/pull/37260
Reported by: David Coudert
Reviewer(s): John H. Palmieri
