Added some documentation

[valerian-chen]

Hey @ZedThree, I'm afraid I can't get the bulleted list in 'output parameters' to work. What am I doing wrong?

[ZedThree]

Ah, you're missing a blank line before the start:

Saved in data_input

* launch_K - initial wavevector
* launch_position - initial position
* mode_flag - polarisation
See `beam_me_up` for a detailed description of input parameters.

Saved in data_output

* q_R_array - beam trajectory, R coordinate
* q_zeta_array - beam trajectory, zeta coordinate
* q_Z_array - beam trajectory, Z coordinate

Saved in analysis_output

* Psi_xx_output - xx component of Psi_w
* Psi_xy_output - xy component of Psi_w
* Psi_yy_output - yy component of Psi_w

That should work