Tweak validator comments

[mds1]

In 044f877 @owocki changed one of the contribution fields to use 18 decimals. The previous value of 4 decimals was causing the tx validator to incorrectly report some txs as failed.

This PR builds on that to just tweak the validator comments so that when they do fail we can get a little bit more info as to why

cc @octavioamu @thelostone-mc

[codecov]

Codecov Report

Merging #7453 into stable will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           stable    #7453   +/-   ##
=======================================
  Coverage   26.17%   26.17%           
=======================================
  Files         307      307           
  Lines       30604    30604           
  Branches     4528     4528           
=======================================
  Hits         8012     8012           
  Misses      22318    22318           
  Partials      274      274           

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