Fix typo in saturation specific humidity formula in Docs (#55)

* fix typo in qᵛ⁺ formula in docs

* empty line

* tweak docstrings

Author: navidcy

docs/src/thermodynamics.md

@@ -318,10 +318,10 @@ fig
 The saturation specific humidity is
 
 ```math
-qᵛ⁺ ≡ \frac{ρᵛ⁺}{ρ} = \frac{pᵛ⁺}{Rᵐ T} .
+qᵛ⁺ ≡ \frac{ρᵛ⁺}{ρ} = \frac{pᵛ⁺}{ρ Rᵐ T} .
 ```
 
-This is what it looks like:
+and this is what it looks like:
 
 ```@example
 using Breeze

src/Thermodynamics/Thermodynamics.jl

@@ -8,4 +8,4 @@ include("atmosphere_thermodynamics.jl")
 include("vapor_saturation.jl")
 include("reference_states.jl")
 
-end # module
+end # module

src/Thermodynamics/vapor_saturation.jl

@@ -1,8 +1,8 @@
 """
     saturation_vapor_pressure(T, thermo, phase::CondensedPhase)
 
-Compute the saturation vapor pressure ``pᵛ⁺`` over a liquid surface by integrating
-the Clausius-Clapeyron relation,
+Compute the saturation vapor pressure ``pᵛ⁺`` over a fluid surface at
+`phase` (i.e., liquid or solid) from the Clausius-Clapeyron relation,
 
 ```math
 dpᵛ⁺ / dT = pᵛ⁺ ℒᵛ(T) / (Rᵛ T^2)
@@ -35,6 +35,19 @@ pᵛ⁺(T) = pᵗʳ \\left ( \\frac{T}{Tᵗʳ} \\right )^{Δcᵖ / Rᵛ} \\exp \
 end
 
 # Over a liquid surface
+"""
+    saturation_specific_humidity(T, ρ, thermo, condensed_phase::CondensedPhase)
+
+Compute the saturation specific humidity for a gas at temperature `T`, total
+density `ρ`, `thermo`dynamics, and `condensed_phase` via:
+
+```math
+qᵛ⁺ = pᵛ⁺ / (ρ Rᵛ T)
+```
+
+where ``pᵛ⁺`` is the [`saturation_vapor_pressure`](@ref), and ``Rᵛ`` is the specific gas
+constant for water vapor.
+"""
 @inline function saturation_specific_humidity(T, ρ, thermo, condensed_phase::CondensedPhase)
     p★ = saturation_vapor_pressure(T, thermo, condensed_phase)
     Rᵛ = vapor_gas_constant(thermo)