feat: serve notprepped rfc xml from datatracker

[rjsparks]

Adds the "Get Editor Source" button here:

Which leads to:

Claude was used while generating this PR.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.47%. Comparing base (68104b5) to head (a3e1efd).
⚠️ Report is 24 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #10692      +/-   ##
==========================================
+ Coverage   88.44%   88.47%   +0.03%     
==========================================
  Files         330      330              
  Lines       44365    44392      +27     
==========================================
+ Hits        39237    39277      +40     
+ Misses       5128     5115      -13     

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