doc: Remove 3.1.0 release entries from changelog

Remove 3.1.0 release entries from changelog

Signed-off-by: divya pillai <[email protected]>

Author: divipillai

doc/nrf/releases_and_maturity/releases/release-notes-changelog.rst

@@ -113,7 +113,7 @@ Developing with custom boards
 Developing with coprocessors
 ============================
 
-* Added the :ref:`ug_hpf_softperipherals_comparison` documentation page, describing potential use cases and differences between the two solutions.
+|no_changes_yet_note|
 
 Security
 ========
@@ -160,12 +160,6 @@ Matter
 
 |no_changes_yet_note|
 
-* Removed:
-
-  * The nRF Connect Matter Manufacturer Cluster Editor tool page.
-    The tool is now available in the `nRF Connect for Desktop`_ app as the Matter Cluster Editor app.
-    For installation instructions and more information about the tool, see the `Matter Cluster Editor app`_ documentation.
-
 Matter fork
 +++++++++++