Updated required documentation

* Morag Williams, University of Glasgow, [williamm](https://gitlab.cern.ch/williamm)

* Koen Wolters, [kwolters](https://gitlab.cern.ch/kwolters)

* Samuel Wood, University of Oxford, [sam-sw](https://github.com/sam-sw)

* Jixing Ye, University of Trento, [jiye](https://gitlab.cern.ch/jiye)

```math

\begin{aligned}

c_e      &= 0.054 \,\text{ns}\,\text{cm}^{-2} \\

c_e      &= 0.54 \,\text{ns}\,\text{cm}^{-2} \\

\kappa_e &= -0.62 \\

\\

c_h      &= 0.0427 \,\text{ns}\,\text{cm}^{-2} \\

for electrons and holes, respectively.

The parameters for electrons are taken from \[[@Mandic]\], for measurements at a temperature of $`T = -20 \,\text{°C}`$, and

the results extrapolated to $`T = -30 \,\text{°C}`$. A scaling from electrons to holes was performed based on the default

values in Weightfield2 \[[@weightfield2]\].

the results extrapolated to $`T = -30 \,\text{°C}`$. Note that an erratum has been made (see https://iopscience.iop.org/article/10.1088/1748-0221/16/03/E03001), c_e should be 0.54ns instead of 0.054ns.

A scaling from electrons to holes was performed based on the default values in Weightfield2 \[[@weightfield2]\].

This model can be selected in the configuration file via the parameter `trapping_model = "mandic"`.

     * @brief Mandic effective trapping model

     *

     * Parametrization taken from https://doi.org/10.1088/1748-0221/15/11/P11018, section 5.

     * The c_e should be 0.54ns instead of 0.054ns, see the erratum from Prof. Mandić https://iopscience.iop.org/article/10.1088/1748-0221/16/03/E03001.

     * Scaling from electrons to holes taken from default beta values in Weightfield2

     */

    class Mandic : virtual public TrappingModel {