misc/ring: fix comment typo

misc/ring.c

@@ -27,8 +27,8 @@
 struct mp_ring {
     uint8_t  *buffer;
 
-    /* Positions of the first readable/writeable chunks. Do not read this
-     * fields but use the atomic private accessors `mp_ring_get_wpos`
+    /* Positions of the first readable/writeable chunks. Do not read these
+     * fields. Use the atomic private accessors `mp_ring_get_wpos`
      * and `mp_ring_get_rpos`. */
     atomic_ullong rpos, wpos;
 };