Release notes for calibration doc changes

re #15544

docs/source/interfaces/Engineering_Diffraction.rst

@@ -39,6 +39,7 @@ RB Number
   likely because the file specified has not been found. Error message
   can be viewed by hovering over the red star sign.
 
+.. _ui engineering calibration:
 
 Calibration
 -----------

docs/source/release/v3.7.0/diffraction.rst

@@ -5,6 +5,11 @@ Diffraction Changes
 .. contents:: Table of Contents
    :local:
 
+Documentation
+-------------
+
+- The documentation for all calibration approaches, including Powder diffrction, single crystal and engineering calibrations has been pulled together, and expanded :ref:`here<Calibration>`.
+
 Crystal Improvements
 --------------------
 

docs/source/release/v3.7.0/direct_inelastic.rst

@@ -9,6 +9,7 @@ Improvements
 ------------
 
 - New CNCS formula to calculate T0 accounts for different phasing of the choppers since August 2015
+- The documentation for all calibration approaches, including PSD tube calibration has been pulled together :ref:`here<Calibration>`
 
 `Full list of changes on GitHub <http://github.com/mantidproject/mantid/pulls?q=is%3Apr+milestone%3A%22Release+3.7%22+is%3Amerged+label%3A%22Component%3A+Direct+Inelastic%22>`_
 

docs/source/release/v3.7.0/ui.rst

@@ -109,6 +109,9 @@ Documentation
   and also concrete equations that describe them
   `#15064 <https://github.com/mantidproject/mantid/pull/15064>`_
 
+- The documentation for all calibration approaches has been pulled together, improved and expanded :ref:`here<Calibration>`.
+
+
 Bugs Resolved
 -------------