Two tiny changes to core.relax_integer_vars

[emma58]

Fixes # .

Summary/Motivation:

@jsiirola gave me an accidental merge of #3586 last week, but this implements a couple (small) suggestions he had to the rewrite of the core.relax_integer_vars transformation

Changes proposed in this PR:

• Fixes a copy-paste typo in a docstring
• Remembers that subclasses of Block other than Disjunct exist. :P

Legal Acknowledgement

By contributing to this software project, I have read the contribution guide and agree to the following terms and conditions for my contribution:

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.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.94%. Comparing base (88940a9) to head (bee3e61).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3645      +/-   ##
==========================================
+ Coverage   88.89%   88.94%   +0.05%     
==========================================
  Files         888      888              
  Lines      102448   102449       +1     
==========================================
+ Hits        91071    91126      +55     
+ Misses      11377    11323      -54     

Flag	Coverage Δ
builders	26.68% <50.00%> (+0.01%)	⬆️
default	85.53% <100.00%> (?)
expensive	34.04% <50.00%> (?)
linux	86.75% <100.00%> (-1.90%)	⬇️
linux_other	86.75% <100.00%> (+0.06%)	⬆️
osx	83.05% <100.00%> (+<0.01%)	⬆️
win	84.95% <100.00%> (-0.01%)	⬇️
win_other	84.95% <100.00%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.