chore: fixes the description of the index of leafHash in the absence proof

[staheri14]

Overview

This PR intends to bring the description of the leafHash field in the Proof data structure in line with the specification. Additionally, among the three criteria enumerated for the leafHash the third criterion is redundant since it is already covered by the first two. Although this has already been addressed in the specification, the code description needs to be updated, and this PR accomplishes that (this comment was originally raised in #110 (comment)).

Checklist

• New and updated code has appropriate documentation
• New and updated code has new and/or updated testing
• Required CI checks are passing
• Visual proof for any user facing features like CLI or documentation updates
• Linked issues closed with keywords

[codecov]

Codecov Report

Merging #114 (39cdb65) into master (6e4a5c3) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #114   +/-   ##
=======================================
  Coverage   96.31%   96.31%           
=======================================
  Files           6        6           
  Lines         461      461           
=======================================
  Hits          444      444           
  Misses         11       11           
  Partials        6        6           

Impacted Files	Coverage Δ
nmt.go	98.82% <ø> (ø)
proof.go	96.73% <ø> (ø)

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.