Add link to notebook in Howto's and update changelog

doc/changelog.rst

@@ -26,6 +26,7 @@ unreleased
     -  Add reflectivity routine :mr:`218`
     -  Possibility to extract run values of mnemonics :mr:`220`
     -  Add get_undulator_config function :mr:`225`
+    -  Add Viking spectrometer analysis class :mr:`240`
 
 1.6.0
 -----

doc/howtos.rst

@@ -169,5 +169,9 @@ Point detectors
 ---------------
 Detectors that produce one point per pulse, or 0D detectors, are all handled in a similar way. Such detectors are, for instance, the X-ray Gas Monitor (XGM), the Transmitted Intensity Monitor (TIM), the electron Bunch Arrival Monitor (BAM) or the photo diodes monitoring the PP laser.
 
+Viking spectrometer
+-------------------
+
+* :doc:`Analysis of Viking spectrometer data <Analysis_of_Viking_spectrometer_data>`.
 
 .. _pyFAI: https://pyfai.readthedocs.io