Update Simulation_parameters_doc.md

Author: lmether

Simulation_parameters_doc.md

@@ -17,7 +17,7 @@ By choosing ```"Synchrotron"``` as machine class it is possible to define all pa
 ```python
 machine_class = 'Synchrotron'
 ```
-The description of the accelerator is provided by providing the following parameters that are required to define a PyHEADTAIL synchrotron. They are individually described in the [PyHEADTAIL documentation](https://giadarol.github.io/PyHEADTAIL/PyHEADTAIL.machines.html#PyHEADTAIL.machines.synchrotron.Synchrotron).
+The description of the accelerator is defined by providing the following parameters that are required to define a PyHEADTAIL synchrotron. They are individually described in the [PyHEADTAIL documentation](https://giadarol.github.io/PyHEADTAIL/PyHEADTAIL.machines.html#PyHEADTAIL.machines.synchrotron.Synchrotron).
 ```python
 optics_mode = 'smooth'
 charge = qe