Fix clippy warnings from Rust v1.59.0

[thanethomson]

Updates to address clippy warnings/errors in Rust v1.59.0.

[codecov-commenter]

Codecov Report

Merging #1097 (9780642) into master (33a4841) will increase coverage by 0.0%.
The diff coverage is 70.5%.

@@          Coverage Diff           @@
##           master   #1097   +/-   ##
======================================
  Coverage    64.7%   64.7%           
======================================
  Files         240     240           
  Lines       20727   20789   +62     
======================================
+ Hits        13416   13458   +42     
- Misses       7311    7331   +20     

Impacted Files	Coverage Δ
light-client/src/evidence.rs	9.0% <0.0%> (ø)
p2p/src/error.rs	0.0% <ø> (ø)
rpc/src/abci/transaction.rs	32.3% <0.0%> (ø)
light-client/src/components/scheduler.rs	77.7% <66.6%> (-9.4%)	⬇️
light-client/src/peer_list.rs	90.2% <83.3%> (+1.7%)	⬆️
config/src/config.rs	55.1% <100.0%> (-1.5%)	⬇️
light-client/src/light_client.rs	74.7% <100.0%> (+2.9%)	⬆️
light-client/src/state.rs	33.3% <100.0%> (ø)
tendermint/src/evidence.rs	21.6% <100.0%> (ø)
... and 8 more

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