docs(changelog): add #1445 fragment

changelog.d/1445-annotation-label-units.md

@@ -0,0 +1,3 @@
+- Label a route, arrow or drawn line of 995 m or more as 1.0 km, and of
+  9,950 m or more as 10 km. The placed label picked the unit before rounding,
+  so it read "1000 m" and "10.0 km" (Aditya, @Rohilalala, #1445).