CLEANUP: mux-h2/traces: better align user messages

"sent H2 request" was already misaligned with the 3 other ones
(sent/rcvd, request/response), and now with "new H2 connection" that's
yet another alignment making the traces even less legible. Let's just
realign all 5 messages, this even eases quick pointer comparisons. This
should probably be backported to 2.4 as it's where it's the most likely
to be used in the mid-term.
diff --git a/src/mux_h2.c b/src/mux_h2.c
index 79e5b3b..dfd437e 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -2728,7 +2728,7 @@
 	if (h2s->id > h2c->max_id)
 		h2c->max_id = h2s->id;
 
-	TRACE_USER("rcvd H2 request ", H2_EV_RX_FRAME|H2_EV_RX_HDR|H2_EV_STRM_NEW, h2c->conn, 0, &rxbuf);
+	TRACE_USER("rcvd H2 request  ", H2_EV_RX_FRAME|H2_EV_RX_HDR|H2_EV_STRM_NEW, h2c->conn, 0, &rxbuf);
 	return h2s;
 
  conn_err:
@@ -2833,7 +2833,7 @@
 		h2s->flags &= ~H2_SF_BLK_MBUSY;
 	}
 
-	TRACE_USER("rcvd H2 response", H2_EV_RX_FRAME|H2_EV_RX_HDR, h2c->conn, 0, &h2s->rxbuf);
+	TRACE_USER("rcvd H2 response ", H2_EV_RX_FRAME|H2_EV_RX_HDR, h2c->conn, 0, &h2s->rxbuf);
 	TRACE_LEAVE(H2_EV_RX_FRAME|H2_EV_RX_HDR, h2c->conn, h2s);
 	return h2s;
  fail:
@@ -5156,7 +5156,7 @@
 		outbuf.area[4] |= H2_F_HEADERS_END_STREAM;
 
 	/* commit the H2 response */
-	TRACE_USER("sent H2 response", H2_EV_TX_FRAME|H2_EV_TX_HDR, h2c->conn, h2s, htx);
+	TRACE_USER("sent H2 response ", H2_EV_TX_FRAME|H2_EV_TX_HDR, h2c->conn, h2s, htx);
 	b_add(mbuf, outbuf.data);
 
 	/* indicates the HEADERS frame was sent, except for 1xx responses. For
@@ -5563,7 +5563,7 @@
 		outbuf.area[4] |= H2_F_HEADERS_END_STREAM;
 
 	/* commit the H2 response */
-	TRACE_USER("sent H2 request", H2_EV_TX_FRAME|H2_EV_TX_HDR, h2c->conn, h2s, htx);
+	TRACE_USER("sent H2 request  ", H2_EV_TX_FRAME|H2_EV_TX_HDR, h2c->conn, h2s, htx);
 	b_add(mbuf, outbuf.data);
 	h2s->flags |= H2_SF_HEADERS_SENT;
 	h2s->st = H2_SS_OPEN;