Enhance docstrings

[navidcy]

We should enhance our docstrings to be like, e.g.,

GeophysicalFlows.jl/src/multilayerqg.jl

Lines 554 to 571 in bd1d48c

	"""
	energies(vars, params, grid, sol)
	energies(prob)
	Returns the kinetic energy of each fluid layer KE``_1, ...,`` KE``_{n}``, and the
	potential energy of each fluid interface PE``_{3/2}, ...,`` PE``_{n-1/2}``, where ``n``
	is the number of layers in the fluid. (When ``n=1``, only the kinetic energy is returned.)
	The kinetic energy at the ``j``-th fluid layer is
	```math
	\\textrm{KE}_j = \\frac{H_j}{H} \\int \\frac1{2} |\\boldsymbol{\\nabla} \\psi_j|^2 \\frac{\\mathrm{d}^2 \\boldsymbol{x}}{L_x L_y} \\ , \\quad j = 1, \\dots, n \\ ,
	```
	while the potential energy that corresponds to the interface ``j+1/2`` (i.e., interface between the ``j``-th and ``(j+1)``-th fluid layer) is
	```math
	\\textrm{PE}_{j+1/2} = \\int \\frac1{2} \\frac{f_0^2}{g'_{j+1/2}} (\\psi_j - \\psi_{j+1})^2 \\frac{\\mathrm{d}^2 \\boldsymbol{x}}{L_x L_y} \\ , \\quad j = 1, \\dots, n-1 \\ .
	```
	"""
	function energies(vars, params, grid, sol)

and then include them in the documentation, e.g.,

GeophysicalFlows.jl/docs/src/modules/multilayerqg.md

Lines 69 to 71 in 0e5d21f

	```@docs
	GeophysicalFlows.MultilayerQG.energies
	```