Parameter documentation hard to find

[Jann Launer]

Other than variables, which will be documented in the math yaml-files (and can then be rendered in the docs), parameters are nowhere defined or described.

What can be done about it? The most consistent approach that comes to mind is to define parameters in the math yaml-files, too. Doing this would complete the mathematical representation of the problem, all in one place: parameters, variables, constraints and objective.

This might be a lot of work. On the other hand, defining all parameters could have other benefits, e.g. protect against typos.

Update: Actually, parameters are documented in defaults (https://calliope.readthedocs.io/en/stable/user/config_defaults.html#per-tech-constraints and https://calliope.readthedocs.io/en/stable/user/config_defaults.html#per-tech-costs). Can make it easier to find by linking it more prominently in the docs chapter on mathematical formulation (https://calliope.readthedocs.io/en/stable/user/ref_formulation.html#)