fix: restore LaTeX subscripts on Hadwiger constant page

[Chessing234]

Summary

• Restore normal LaTeX subscripts in the 39a constant description (C_{39}, H_3).
• Same regression as fix: restore LaTeX subscripts on Ihara constant page #116–fix: restore LaTeX subscripts on tight knot constant page #119: merged fix: escape inline subscripts on Hadwiger constant page #111 escaped underscores inside $...$ math.

Test plan

• Open the 39a constant page and confirm subscripts render in the description.

Made with Cursor

[Chessing234]

Same story as #120 — #111 broke C_{39} and H_3 in the Hadwiger description line.