doc: release-notes: add linear range API
Add notes about the linear_range.h API.
@@ -851,6 +851,11 @@ Libraries / Subsystems
* Replaced all :c:func:`k_panic` invocations within settings backend
initialization with returning / propagating error codes.
+* Utilities
+
+ * Added the linear range API to map values in a linear range to a range index
+ :zephyr_file:`include/zephyr/sys/linear_range.h`.
+
HALs
****
