Fix a formatting issue in the algo module's docs (#437)
Fix a formatting issue in the algo module's docs (#437)

The (long) URL in the doc comment of `fn all_simple_paths` causes a formatting issue on e.g. <https://docs.rs/petgraph/0.5.1/petgraph/algo/index.html>.

This commit moves it to a new paragraph so that it gets omitted from the module's short description.
petgraph/petgraph