Add an example demonstrating how to send and receive events in the same system #35574

Job	Run time
build (windows-latest)	4m 48s
check-bevy-internal-imports	3s
build (ubuntu-latest)	1m 53s
build (macos-latest)	2m 25s
check-doc	5m 18s
check-missing-examples-in-docs	32s
ci	1m 56s
miri	6m 30s
run-examples-on-windows-dx12	14m 24s
toml	3s
check-missing-features-in-docs	31s
markdownlint	1m 9s
check-compiles	2m 26s
build-wasm	36s
msrv	54s
	43m 28s

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