style: satisfy golangci-lint on the round-6 changes

nolintlint: gosec was not firing on the deferred Close.
nonamedreturns + varnamelen in collapseUserModeOps.

internal/ircserver/conn.go

@@ -161,7 +161,7 @@ func (c *Conn) Disconnect(reason string) {
 func (c *Conn) notifyKilledAndClose(
 	nick, host, reason string,
 ) {
-	defer c.conn.Close() //nolint:errcheck,gosec
+	defer c.conn.Close() //nolint:errcheck
 
 	c.sendWithin(
 		killWriteWindow,