Update documentation

Author: devmotion

docs/src/api.md

@@ -1,32 +1,13 @@
 # API
 
-```@meta
-DocTestSetup  = quote
-    using InverseFunctions
-end
-```
-
-## Modules
-
-```@index
-Order = [:module]
-```
-
-## Types and constants
-
-```@index
-Order = [:type, :constant]
-```
-
-## Functions and macros
+## Interface
 
-```@index
-Order = [:macro, :function]
+```@docs
+inverse
 ```
 
-# Documentation
+## Test utility
 
-```@autodocs
-Modules = [InverseFunctions]
-Order = [:module, :type, :constant, :macro, :function]
+```@docs
+InverseFunctions.test_inverse
 ```

docs/src/index.md

@@ -1,5 +1,9 @@
 # InverseFunctions.jl
 
+```@docs
+InverseFunctions
+```
+
 This package defines the function [`inverse`](@ref). `inverse(f)` returns the inverse function of a function `f`, so that `inverse(f)(f(x)) ≈ x`.
 
 `inverse` supports mapped/broadcasted functions (via `Base.Fix1`) and (on Julia >=v1.6) function composition.