Docs: Fix doctest failures in align.py

[IAyaanHere]

Docs: Fix failing doctests in MDAnalysis.analysis.align

Fixed failing doctests in package/MDAnalysis/analysis/align.py caused by NumPy scalar types and non-deterministic memory addresses.

Details:

1. NumPy Scalars & Mixed Types:
   Functions like rmsd() and alignto() are now returning np.float64 (or a mixed tuple of np.float64 and float) instead of just plain floats. I updated the docstrings to match the actual output.

   Before (Failing):

   Expected:
       (21.892591663632704, 6.809396586471809)
   Got:
       (np.float64(21.892591663632704), 6.809396586471809)
   
   

2. Memory Address (RAM) Issue: The AlignTraj example was failing because the object print includes a memory address (e.g., 0x00...), which changes on every run. The standard ellipsis ... wasn't catching it properly on my environment.

Before (Failing):

Expected:
<MDAnalysis.analysis.align.AlignTraj object at ...>
Got:
<MDAnalysis.analysis.align.AlignTraj object at 0x000001D789C0F770>

After: Suppressed the output using _ = ... to make the test deterministic.

Verification: Ran tests locally: pytest --doctest-modules package/MDAnalysis/analysis/align.py Result: 2 passed (All warnings unrelated to changes).

LLM / AI generated code disclosure
LLMs or other AI-powered tools (beyond simple IDE use cases) were used in this contribution: no

PR Checklist

• Issue raised/referenced?
• Tests updated/added?
• Documentation updated/added?
• package/CHANGELOG file updated?
• Is your name in package/AUTHORS?
• LLM/AI disclosure was updated.

Developers Certificate of Origin
I certify that I can submit this code contribution as described in the Developer Certificate of Origin, under the MDAnalysis LICENSE.

---

📚 Documentation preview 📚: https://mdanalysis--5207.org.readthedocs.build/en/5207/

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.72%. Comparing base (9cbc8ea) to head (6162231).
⚠️ Report is 1 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #5207   +/-   ##
========================================
  Coverage    92.72%   92.72%           
========================================
  Files          180      180           
  Lines        22475    22475           
  Branches      3190     3190           
========================================
  Hits         20841    20841           
  Misses        1177     1177           
  Partials       457      457           

☔ 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.