chore: fix inconsistent comment for dividePoint()

[jaeseung-bae]

Description

• (audit issue) fix comment by hiding details.
  • Problem: The divider is assigned with math.MaxInt64 + 1 which does not align with the comment x÷(MaxUint64+1)×y.
    • Comment: // dividePoint computes x÷(MaxUint64+1)×y without overflow for uint64. ...
    • Actual code: math.MaxInt64 + 1

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 66.57%. Comparing base (1279868) to head (f89862b).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #769      +/-   ##
==========================================
+ Coverage   66.52%   66.57%   +0.05%     
==========================================
  Files         285      285              
  Lines       37917    37917              
==========================================
+ Hits        25224    25243      +19     
+ Misses      10887    10868      -19     
  Partials     1806     1806              

Files	Coverage Δ
types/validator_set.go	91.13% <ø> (ø)

... and 14 files with indirect coverage changes