[h5_to_nx] update documentation regarding the set-params option.

/close #35

doc/tutorials/tomoh52nx.rst

@@ -110,5 +110,7 @@ nxtomomill tomoh52nx --help
   --set-params [SET_PARAMS [SET_PARAMS ...]]
                         Allow manual definition of some parameters. Valid
                         parameters (and expected input unit) are: energy
-                        (kev).
+                        (kev). Should be added at the end of the command line
+                        because will try to cover all text set after this
+                        option.
 ```
\ No newline at end of file

nxtomomill/app/tomoh52nx.py

@@ -240,7 +240,9 @@ def main(argv):
         nargs="*",
         help="Allow manual definition of some parameters. "
         "Valid parameters (and expected input unit) "
-        "are: {}.".format(_getPossibleInputParams()),
+        "are: {}. Should be added at the end of the command line because "
+        "will try to cover all text set after this "
+        "option.".format(_getPossibleInputParams()),
     )
     options = parser.parse_args(argv[1:])