fix: use net::discv5 for reth's discv5 tracing target namespace (reverts #12045)

[zilayo]

The tracing target for Reth's discv5 logs was changed from net::discv5 to discv5 in PR #12045 (fixed issue #12043)

Currently none of these traces are logged as there is a default directive discv5=off which is applied from DEFAULT_ENV_FILTER_DIRECTIVES. These are applied after the directives from RUST_LOG, so even if RUST_LOG=discv5=trace is used, this is overridden with discv5=off

reth/crates/tracing/src/layers.rs

Lines 22 to 28 in ddc9bda

	const DEFAULT_ENV_FILTER_DIRECTIVES: [&str; 5] = [
	"hyper::proto::h1=off",
	"trust_dns_proto=off",
	"trust_dns_resolver=off",
	"discv5=off",
	"jsonrpsee-server=off",
	];

The discv5 external crate traces were initially disabled in PR #7458 due to noise.

This PR simply removes discv5=off from DEFAULT_ENV_FILTER_DIRECTIVES.

If it's still deemed that the discv5 external crate logs are too verbose and that this should remain turned off, then #12045 will need to be reverted or reth's discv5 crate target renamed.

[mattsse]

If it's still deemed that the discv5 external crate logs are too verbose and that this should remain turned off, then #12045 will need to be reverted or reth's discv5 crate target renamed.

ah right, that's why we used the net prefix in the first place.
the discv5 crate has a bunch of warns that we don't really want, so we should rather revert #12045

do you want to revert #12045 instead?

[zilayo]

If it's still deemed that the discv5 external crate logs are too verbose and that this should remain turned off, then #12045 will need to be reverted or reth's discv5 crate target renamed.

ah right, that's why we used the net prefix in the first place. the discv5 crate has a bunch of warns that we don't really want, so we should rather revert #12045

do you want to revert #12045 instead?

#12045 has been reverted and i renamed a few stragglers from discv5 -> net::discv5