docs(examples): add HTTP/2 server example (#3702) #2853

Job	Run time
Verify hyper.h is up to date	40s
semver	17s
Check Style	8s
minimal-versions	39s
Test with Miri	2m 33s
Test C API (FFI)	17s
features	39s
Check MSRV	34s
udeps	23s
Test stable on ubuntu-latest	1m 6s
Test stable on windows-latest	3m 18s
Test stable on macOS-latest	1m 16s
Test beta on ubuntu-latest	1m 10s
Test beta on windows-latest	1m 47s
Test beta on macOS-latest	1m 16s
Test nightly on ubuntu-latest	1m 24s
Test nightly on windows-latest	2m 27s
Test nightly on macOS-latest	1m 31s
Check exposed types	21s
Build docs	22s
CI is green	1s
	22m 9s

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