Fix hidden constructors warnings (#16)

* Fix `HiddenConstructors` warnings

* Update changelog

Author: kl0tl

CHANGELOG.md

@@ -6,6 +6,8 @@ Notable changes to this project are documented in this file. The format is based
 
 Breaking changes (😱!!!):
 
+- Removed `Newtype` instance for `TacitString`
+
 New features:
 
 Bugfixes:

src/Data/TacitString.purs

@@ -4,11 +4,9 @@ module Data.TacitString
   ) where
 
 import Prelude
-import Data.Newtype (class Newtype)
 
 newtype TacitString = TacitString String
 
-derive instance newtypeTacitString :: Newtype TacitString _
 derive instance eqTacitString :: Eq TacitString
 derive instance ordTacitString :: Ord TacitString