add docs to sim init code

[haakon-e]

This pull request primarily improves code readability and maintainability in src/solver/type_getters.jl by reformatting code for consistency, adding helpful docstrings to key functions, and simplifying multi-line statements. There are no functional changes to the logic, but the code is now easier to read, understand, and maintain.

Documentation improvements:

• Added docstrings to important functions such as get_atmos, get_numerics, get_spaces, ode_configuration, and get_sim_info, providing clear explanations of their purpose and usage. [1] [2] [3] [4] [5]

Code formatting and readability:

• Reformatted multi-line assignments and function calls into single lines where appropriate, reducing unnecessary line breaks and improving code clarity throughout the file. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19]

Warnings and error messages:

• Reformatted warning and error messages to use single-line strings or more readable multi-line strings, making logs and errors easier to interpret. [1] [2] [3] [4]

Other minor cleanups:

• Simplified function signatures and removed unnecessary comments or commented-out code. [1] [2]

These changes do not alter any functionality but make the codebase easier to work with and maintain.

[haakon-e]

cc: @nefrathenrici I know you're working on an updated interface for all of this, but if that's still some ways out, I'd propose merging this, which should improve readability of these important functions