Add clearer docs for Prelude module (#270)

Author: JordanMartinez

CHANGELOG.md

@@ -12,6 +12,7 @@ Bugfixes:
 
 Other improvements:
 - Changed `unit`'s FFI representation from `{}` to `undefined` (#267 by @JordanMartinez)
+- Added clearer docs for Prelude module (#270 by @JordanMartinez)
 - Clarify docs for `flip` (#271 by @JordanMartinez)
 
 ## [v5.0.1](https://github.com/purescript/purescript-prelude/releases/tag/v5.0.1) - 2021-05-11

src/Prelude.purs

@@ -1,3 +1,15 @@
+-- | `Prelude` is a module that re-exports many other foundational modules from the `purescript-prelude` library
+-- | (e.g. the Monad type class hierarchy, the Monoid type classes, Eq, Ord, etc.).
+-- |
+-- | Typically, this module will be imported in most other libraries and projects as an open import.
+-- |
+-- | ```
+-- | module MyModule where
+-- |
+-- | import Prelude -- open import
+-- |
+-- | import Data.Maybe (Maybe(..)) -- closed import
+-- | ```
 module Prelude
   ( module Control.Applicative
   , module Control.Apply