Add code references to gas solid contactors docs

[bpaul4]

Fixes

Clarifies code reference requested by #1446.

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[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 76.35%. Comparing base (80d37a8) to head (889e58c).
Report is 26 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1451      +/-   ##
==========================================
- Coverage   76.36%   76.35%   -0.01%     
==========================================
  Files         394      394              
  Lines       64953    64953              
  Branches    14404    14404              
==========================================
- Hits        49601    49598       -3     
- Misses      12793    12797       +4     
+ Partials     2559     2558       -1     

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[MarcusHolly]

LGTM

[lbianchi-lbl]

@aostace01 do you think you have time for a quick review? There are just a few changes in the docs.

[aostace01]

The changes look good to me.