Fix new nightly clippy lints

[jtescher]

No description provided.

[codecov]

Codecov Report

Merging #400 (5fd028c) into master (c56866b) will decrease coverage by 0.15%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master     #400      +/-   ##
==========================================
- Coverage   49.28%   49.12%   -0.16%     
==========================================
  Files          66       66              
  Lines        5377     5394      +17     
==========================================
  Hits         2650     2650              
- Misses       2727     2744      +17     

Impacted Files	Coverage Δ
opentelemetry/src/api/metrics/number.rs	31.38% <0.00%> (-4.45%)	⬇️
...telemetry/src/sdk/metrics/aggregators/histogram.rs	0.00% <0.00%> (ø)

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[TommyCpp]

LGTM:+1: