Requested documentation improvement

See discussion in #634

Currently we instruct people running the tutorials to use Python 3.13+, however it would be nice if they ran without error for any version of Python that you can install pygambit into, which I currently is 3.10-3.14

• Fix formatting issue highlighted in Fix floating formatting #634
• Update GitHub actions as required
• Update docs
• Close [Bug]: Rational cannot be formatted using float specification in notebook tests #633