Add tokio taskname registration for use in tokio-console #630

Job	Run time
Documentation	12s
Lints	44s
Build Examples	2m 37s
Minimal Dependency Versions	1m 6s
Build (aarch64-unknown-linux-gnu)	35s
Minimal Dependency Versions (MSRV)	31s
Build (x86_64-pc-windows-gnu)	55s
Build (x86_64-unknown-linux-gnu)	33s
Minimum Supported Rust Version	22s
Test Suite	3m 57s
Semantic Versioning	21s
Memory leaks	3m 48s
Publish version	0s
	15m 41s

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