chore: miner: fix comment in light of FIP-0029

[arajasek]

No description provided.

[codecov-commenter]

Codecov Report

Merging #649 (930aeb9) into master (fe531cb) will increase coverage by 0.20%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #649      +/-   ##
==========================================
+ Coverage   82.21%   82.41%   +0.20%     
==========================================
  Files          88       88              
  Lines       18306    18293      -13     
==========================================
+ Hits        15050    15077      +27     
+ Misses       3256     3216      -40     

Impacted Files	Coverage Δ
actors/miner/src/lib.rs	71.51% <ø> (+0.57%)	⬆️
state/src/check.rs	87.23% <0.00%> (-0.43%)	⬇️
actors/power/src/lib.rs	84.11% <0.00%> (-0.43%)	⬇️
actors/market/src/lib.rs	81.46% <0.00%> (-0.10%)	⬇️
runtime/src/util/message_accumulator.rs	94.54% <0.00%> (+0.90%)	⬆️
actors/cron/src/lib.rs	93.10% <0.00%> (+3.44%)	⬆️
actors/miner/src/deadline_info.rs	96.62% <0.00%> (+16.85%)	⬆️