Fix clippy warning #1031

Job	Run time
Test (macOS)	1m 42s
Check minimal versions	1m 3s
Test (nightly)	2m 5s
Test (stable)	2m 29s
Test (beta)	2m 57s
Examples	2m 54s
Test (Windows)	6m 10s
MSRV	0s
Build docs	59s
Test (native-tls)	2m 34s
Test (no default features)	58s
Test (no cache)	2m 27s
Test (no gateway)	1m 47s
Test (unstable Discord API features)	3m 6s
Test (zlib compression)	2m 36s
Test (zstd compression)	2m 40s
Test (zlib and zstd compression)	2m 54s
Test (chrono, chrono)	1m 1s
Test (unstable API + typesize, default unstable typesize, true)	1m 11s
Test (builder without model, builder, true)	44s
Test (unstable Discord API (no default features), unstable, true)	46s
	43m 3s

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