doc: release-notes: Add C library release notes

This commit adds the C library release notes for the Zephyr 3.3
release.

Signed-off-by: Stephanos Ioannidis <[email protected]>

Author: stephanosio

doc/releases/release-notes-3.3.rst

@@ -20,6 +20,11 @@ API Changes
 Changes in this release
 =======================
 
+* Newlib nano variant is no longer selected by default when
+  :kconfig:option:`CONFIG_NEWLIB_LIBC` is selected.
+  :kconfig:option:`CONFIG_NEWLIB_LIBC_NANO` must now be explicitly selected in
+  order to use the nano variant.
+
 * Bluetooth: Add extra options to bt_le_per_adv_sync_transfer_subscribe to
   allow disabling sync reports, and enable sync report filtering. these two
   options are mutually exclusive.
@@ -768,6 +773,15 @@ Devicetree
 Libraries / Subsystems
 **********************
 
+* C Library
+
+  * Newlib nano variant is no longer selected by default when
+    :kconfig:option:`CONFIG_NEWLIB_LIBC` is selected.
+    :kconfig:option:`CONFIG_NEWLIB_LIBC_NANO` must now be explicitly selected
+    in order to use the nano variant.
+  * Picolibc now supports all architectures supported by Zephyr.
+  * Added C11 ``aligned_alloc`` support to the minimal libc.
+
 * C++ Library
 
   * C++ support in Zephyr is no longer considered a "subsystem" because it