Fix lints reported by clippy 0.1.57

[mzabaluev]

The new lints pop up in the CI for multiple PRs.

• Referenced an issue explaining the need for the change
• Updated all relevant documentation in docs
• Updated all code comments where relevant
• Wrote tests
• Added entry in .changelog/

[codecov-commenter]

Codecov Report

Merging #1041 (55d4ffd) into master (0a53b18) will increase coverage by 0.1%.
The diff coverage is 50.0%.

@@           Coverage Diff            @@
##           master   #1041     +/-   ##
========================================
+ Coverage    62.0%   62.1%   +0.1%     
========================================
  Files         237     237             
  Lines       21168   21140     -28     
========================================
+ Hits        13128   13132      +4     
+ Misses       8040    8008     -32     

Impacted Files	Coverage Δ
rpc/src/endpoint/validators.rs	0.0% <0.0%> (ø)
rpc/src/event.rs	6.4% <0.0%> (ø)
tendermint/src/evidence.rs	21.6% <0.0%> (ø)
light-client/src/fork_detector.rs	79.0% <40.0%> (ø)
testgen/src/tester.rs	68.7% <50.0%> (ø)
rpc/src/abci/info.rs	57.1% <100.0%> (+17.1%)	⬆️
rpc/src/abci/responses.rs	50.0% <100.0%> (-5.2%)	⬇️
rpc/src/client/transport/mock.rs	88.1% <100.0%> (+0.2%)	⬆️
rpc/src/client/transport/router.rs	74.5% <100.0%> (-0.3%)	⬇️
tendermint/src/block/round.rs	83.6% <100.0%> (-0.9%)	⬇️
... and 7 more

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