Documentation Tweaks for contrib.alternative_solutions

[viens-code]

Fixes # .

Adds documentation details to contrib.alternative_solutions

Summary/Motivation:

Adds documentation details to contrib.alternative_solutions

Changes proposed in this PR:

• Adds citation to contrib/alternative_solutions/balas.py to original Balas 1972 paper "Canonical Cuts on the Unit Hypercube"
• Adds example to documentation for alternative_solutions demonstrating how to use abs_opt_gap to limit generated solutions to those within a given optimality gap

Legal Acknowledgement

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1. I agree my contributions are submitted under the BSD license.
2. I represent I am authorized to make the contributions and grant the license. If my employer has rights to intellectual property that includes these contributions, I represent that I have received permission to make contributions and grant the required license on behalf of that employer.

[mrmundt]

@viens-code - Please install the most recent version of black into your environment and run black -S -C on your files.

[mrmundt]

@viens-code - black is still not your friend. Please make sure you have the most recent version installed and try again.

[emma58]

@mrmundt @viens-code I think black passed--this one's a typo.

[mrmundt]

@viens-code - Whooops, you're right, sorry, I was looking at the last job. Fix the typo, commit, push, and it'll keep going!

[viens-code]

Yeah, I think I figured out what were the issues with black.
Hopefully things work now.
Didn't expect it to spell check my comments "Cannonical" is apparently not the canonical spelling for that word

[jsiirola]

@viens-code, can you make this PR against the doc-reorg branch instead on main? Merging this here would cause a bunch of merge conflicts with that effort.

[viens-code]

Closed in favor of #3370 per @jsiirola request to move branch