gh-38321: Implemented generators for some small graphs/ digraphs
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This PR adds generators for the Bicorn graph, the Tricorn graph, the
Murty graph, the KohTindell digraph, the Cubeplex Graph and the Twinplex
graph.
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description below. -->
<!-- ^ For example, instead of "Fixes #12345" use "Introduce new method
to calculate 1 + 2". -->
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This PR introduces new static methods, specifically `BicornGraph`,
`TricornGraph`, `MurtyGraph`, `KohTindellDiGraph`, `CubeplexGraph` and
`TwinplexGraph`.
<!-- v Why is this change required? What problem does it solve? -->
There is no current implementation of the generators for the above
mentioned graphs/ digraphs.
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example, "Fixes #12345". -->
Fixes #38320.
### :memo: Checklist
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- [x] The title is concise and informative.
- [x] The description explains in detail what this PR is about.
- [x] I have linked a relevant issue or discussion.
- [ ] I have created tests covering the changes.
- [ ] I have updated the documentation and checked the documentation
preview.
### :hourglass: Dependencies
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Nothing as of now (up to my knowledge).
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cc: @dcoudert.
URL: https://github.com/sagemath/sage/pull/38321
Reported by: Janmenjaya Panda
Reviewer(s): David Coudert, Janmenjaya Panda
