Fix docs issue on release 8.2

[JCGoran]

Backport of #2229 that fixes #2710, at least on RTD (see https://readthedocs.org/projects/nrn/builds/23439484/).
Locally the issue still persists so I am inclined to keep that issue open in case someone wants to debug it thoroughly.

[sonarcloud]

Quality Gate passed

Issues
0 New issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[codecov]

Codecov Report

Attention: 14 lines in your changes are missing coverage. Please review.

Comparison is base (1d87d5d) 46.51% compared to head (2219c40) 46.56%.
Report is 1 commits behind head on release/8.2.

Files	Patch %	Lines
share/lib/python/neuron/rxd/species.py	44.44%	10 Missing ⚠️
share/lib/python/neuron/rxd/region.py	50.00%	4 Missing ⚠️

Additional details and impacted files

@@               Coverage Diff               @@
##           release/8.2    #2739      +/-   ##
===============================================
+ Coverage        46.51%   46.56%   +0.04%     
===============================================
  Files              527      527              
  Lines           119267   119282      +15     
===============================================
+ Hits             55474    55540      +66     
+ Misses           63793    63742      -51     

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[azure-pipelines]

✔️ 2219c40 -> Azure artifacts URL