Make launchAff_ only work on Aff Unit (#203)

Co-authored-by: Thomas Honeyman <admin@thomashoneyman.com>

Author: i-am-the-slime

CHANGELOG.md

@@ -5,6 +5,7 @@ Notable changes to this project are documented in this file. The format is based
 ## [Unreleased]
 
 Breaking changes:
+- Restrict the signature of `launchAff_` to only work on `Aff Unit` (#203 by @i-am-the-slime)
 - Migrate FFI to ES modules (#209 by @JordanMartinez)
 
 New features:

src/Effect/Aff.purs

@@ -226,7 +226,7 @@ launchAff aff = do
   pure fiber
 
 -- | Forks an `Aff` from an `Effect` context, discarding the `Fiber`.
-launchAff_ :: forall a. Aff a -> Effect Unit
+launchAff_ :: Aff Unit -> Effect Unit
 launchAff_ = void <<< launchAff
 
 -- | Suspends an `Aff` from an `Effect` context, returning the `Fiber`.