updated docs to reflect the new two-argument @returned_quantities

Author: torfjelde

docs/src/api.md

@@ -14,11 +14,11 @@ These statements are rewritten by `@model` as calls of [internal functions](@ref
 @model
 ```
 
-One can nest models and call another model inside the model function with [`@submodel`](@ref) and [`@returned_quantities`](@ref).
+One can nest models and call another model inside the model function with [`@submodel`](@ref) and [`@returned_quantities(model)`](@ref).
 
 ```@docs
 @submodel
-@returned_quantities
+@returned_quantities(model)
 ```
 
 In the context of nesting models, it's also useful to prefix the variables in sub-models to avoid variable names clashing:
@@ -125,10 +125,10 @@ It is possible to manually increase (or decrease) the accumulated log density fr
 @addlogprob!
 ```
 
-Return values of the model function for a collection of samples can be obtained with [`returned_quantities`](@ref).
+Return values of the model function for a collection of samples can be obtained with [`@returned_quantities`](@ref).
 
 ```@docs
-returned_quantities
+@returned_quantities(model, input)
 ```
 
 For a chain of samples, one can compute the pointwise log-likelihoods of each observed random variable with [`pointwise_loglikelihoods`](@ref). Similarly, the log-densities of the priors using