Fix clippy warning #1040

Job	Run time
Build docs	56s
Examples	3m 24s
Test (macOS)	1m 46s
Check minimal versions	1m 1s
MSRV	0s
Test (nightly)	1m 56s
Test (stable)	3m 28s
Test (beta)	2m 57s
Test (Windows)	5m 33s
Test (native-tls)	2m 28s
Test (no default features)	55s
Test (no cache)	2m 24s
Test (no gateway)	1m 50s
Test (unstable Discord API features)	2m 45s
Test (zlib compression)	2m 20s
Test (zstd compression)	2m 13s
Test (zlib and zstd compression)	2m 32s
Test (chrono, chrono)	54s
Test (unstable API + typesize, default unstable typesize, true)	1m 7s
Test (builder without model, builder, true)	47s
Test (unstable Discord API (no default features), unstable, true)	44s
	42m 0s

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