docs(flights): changelog names the one-in-13-ticks rotation, about once a second

changelog.d/870-hidden-contact-dr.md

@@ -1,4 +1,4 @@
 - Reduce dead-reckoning work for flights already hidden behind the horizon.
-  Hidden contacts update on a staggered one-in-12-ticks rotation while visible
+  Hidden contacts update on a staggered one-in-13-ticks rotation (about once a
-  contacts and contacts with fleet models retain the full update path
+  second) while visible contacts and contacts with fleet models retain the full
-  (Wilmer Alzate, #870).
+  update path (Wilmer Alzate, #870).