Rephrase help text and place parameter addition near 'scan' definition

Author: willend

tools/Python/mcrun/mcrun.py

@@ -99,6 +99,11 @@ def add_mcrun_options(parser):
         action='store_true',
         help='Run a multi-dimensional scan')
 
+    add("--scan_split",
+        type=int,
+        metavar="scan_split",
+        help='Scan by parallelising steps as individual cpu threads. Initialise by number of wanted threads (e.g. your number of cores).')
+
     add('--autoplot',
         action='store_true',
         help='Open plotter on generated dataset')
@@ -224,11 +229,6 @@ def add_mcrun_options(parser):
         default="",
     )
 
-    add("--scan_split",
-        type=int,
-        metavar="scan_split",
-        help='Scanning over a variable is split onto individual cpu threads')
-
     #    --optimize-maxiter maxiter  max iter of optimization
     #    --tol tol          tolerance criteria to end the optimization
     #    --method method    Method to maximize the intensity in ['nelder-mead', 'powell', 'cg', 'bfgs', 'newton-cg', 'l-bfgs-b', 'tnc', 'cobyla', 'slsqp', 'trust-constr', 'dogleg', 'trust-ncg', 'trust-exact', 'trust-krylov']