Consolidate docstrings in generators.rs (#1397)

* Consolidate docstrings in generators.rs

* Try to fix identation in generators.rs

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Co-authored-by: Ivan Carvalho <8753214+IvanIsCoding@users.noreply.github.com>

Author: eumiro

docs/source/api/generators.rst

@@ -33,3 +33,4 @@ Generators
     rustworkx.generators.complete_graph
     rustworkx.generators.directed_complete_graph
     rustworkx.generators.dorogovtsev_goltsev_mendes_graph
+    rustworkx.generators.karate_club_graph