Remove reference to JSON argument in documentation of hlt2_check_output

Just a small update in the documentation...

Hlt/Hlt2Conf/options/hlt2_check_output.py

@@ -14,9 +14,14 @@ Runs over the output of the hlt2_all_lines test, manually running the unpackers
 and DecReports decoder, and checks per event that each firing trigger line has
 a non-zero number of Particle objects in the expected location.
 
+When using this script *outside of the QMTests*, please note that it's expected
+all lines to have produced particles. When running over an MC production,
+this means that one needs to take care of skipping over 
+the 'Hlt2MCPassThroughLine'.
+
 Takes command-line arguments:
 
-    python hlt2_check_output.py <DST or MDF file> <HLT2 JSON TCK>
+    python hlt2_check_output.py <DST or MDF file>
 """
 import sys