[h52nx][configuration] add to the EXTRA_PARAMS_ENERGY_VALID_KEYS. Allows to...

[h52nx][configuration] add  to the EXTRA_PARAMS_ENERGY_VALID_KEYS. Allows to display it on the documentation when .cfg is generated

nxtomomill/io/config.py

@@ -263,6 +263,7 @@ class TomoHDF5Config:
         EXTRA_PARAMS_ENERGY_DK,
         EXTRA_PARAMS_X_PIXEL_SIZE_DK,
         EXTRA_PARAMS_Y_PIXEL_SIZE_DK,
+        EXTRA_PARAMS_DISTANCE,
     )
 
     COMMENTS_EXTRA_PARAMS_SECTION = {