Update fix_rhok.txt

doc/src/fix_rhok.txt

@@ -18,7 +18,9 @@ a = anchor point of bias potential :ul
 [Examples:]
 
 fix bias all rhok 16 0 0 4.0 16.0
-fix bias Bs rhok 12 12 0 10.0 24.0 :pre
+fix 1 all npt temp 0.8 0.8 4.0 z 2.2 2.2 8.0
+# output                             U_bias rho_k_RE  rho_k_IM  |rho_k|
+thermo_style custom step temp pzz lz f_bias f_bias\[1\] f_bias\[2\] f_bias\[3\] :pre
 
 [Description:]
 
@@ -27,20 +29,14 @@ The fix applies an force to atoms given by the potential
 :c,image(Eqs/fix_rhok.jpg)
 
 as described in "(Pedersen)"_#Pedersen. 
-The energy and the value of the
-collective density field can be written by including
 
-# output                                U_bias rho_k_RE  rho_k_IM |rho_k| 
-thermo_style custom step temp pzz pe lz f_bias f_bias\[1\] f_bias\[2\] f_bias\[3\] :pre
-
-to the input script.
-
-This field that bias long-range order 
-can be used to study crystal-liquid interfaces,
+This field, that bias configurations with long-range order, 
+can be used to study crystal-liquid interfaces
 and determine melting temperatures "(Pedersen)"_#Pedersen.
-The folder {examples/pinning} of the source code 
-contains an example of using the interface pinning method 
-on the Lennard-Jones system.
+
+An example of using the interface pinning method 
+is located in the folder 
+{examples/USER/pinning} of the source code to LAMMPS.
 
 [Restrictions:]