Minor helptext generation improvements

[brentyi]

• Adjust logic for generating group names. Fixes Configure option group for an option #183
• Fixed edge case for double-nested structures.
• Tests

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.71%. Comparing base (1a9448a) to head (fc14ab4).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #184   +/-   ##
=======================================
  Coverage   99.71%   99.71%           
=======================================
  Files          25       25           
  Lines        2134     2142    +8     
=======================================
+ Hits         2128     2136    +8     
  Misses          6        6           

Flag	Coverage Δ
unittests	99.71% <100.00%> (+<0.01%)	⬆️

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