Suffix user agent with slash

[rithvikvibhu]

Not a big deal, but hnsd user agents don't end with a slash. This was added in hnsd (#81) last year (before hsd handshake-org/hsd#710 a few months ago) and hence the difference.

Taken from a node peer list:

{
  "/hnsd:1.0.0/": 474,
  "/hnsd:1.0.0/beacon": 2,
  "/hsd:4.0.0/": 4,
  "/hsd:4.0.1/bob-wallet:1.0.0/": 1,
  "/hsd:4.0.2/": 7,
}

I think this needs to change?

hnsd/src/pool.c

Lines 305 to 312 in 856ee22

	size_t len = strlen(pool->user_agent);
	len += strlen(user_agent);
	// Agent size in p2p version message is 1 byte
	if (len > 0xff)
	return false;
	pool->user_agent = strcat(pool->user_agent, user_agent);