Remove Documentation.Haddock.Utf8

The circumstances under which this module appeared are completely gone.
The Hyperlinker backend no longer needs this module (it uses the more
efficient `Encoding` module from `ghc`).

Why no deprecation? Because this module really shouldn't exist!

  - It isn't used in `haddock-library`/`haddock-api` anymore
  - It was copy pasted directly from `utf8-string`
  - Folks seeking a boot-lib only solution can use `ghc`'s `Encoding`

Author: harpocrates

haddock-api/haddock-api.cabal

@@ -46,7 +46,7 @@ library
                , Cabal           ^>= 2.3.0
                , ghc             ^>= 8.7
                , ghc-paths       ^>= 0.1.0.9
-               , haddock-library ^>= 1.7.0
+               , haddock-library ^>= 1.8.0
                , xhtml           ^>= 3000.2.2
 
   -- Versions for the dependencies below are transitively pinned by
@@ -170,7 +170,7 @@ test-suite spec
   build-depends: Cabal           ^>= 2.3
                , ghc             ^>= 8.7
                , ghc-paths       ^>= 0.1.0.9
-               , haddock-library ^>= 1.7.0
+               , haddock-library ^>= 1.8.0
                , xhtml           ^>= 3000.2.2
                , hspec           >= 2.4.4 && < 2.6
                , QuickCheck      ^>= 2.11

haddock-library/CHANGES.md

@@ -1,7 +1,10 @@
-## TBA
+## Changes in version 1.8.0
 
  * Support inline markup in markdown-style links (#875)
 
+ * Remove now unused `Documentation.Haddock.Utf8` module.
+   This module was anyways copied from the `utf8-string` package.
+
 ## Changes in version 1.7.0
 
  * Make `Documentation.Haddock.Parser.Monad` an internal module

haddock-library/haddock-library.cabal

@@ -1,6 +1,6 @@
 cabal-version:        2.2
 name:                 haddock-library
-version:              1.7.0
+version:              1.8.0
 synopsis:             Library exposing some functionality of Haddock.
 
 description:          Haddock is a documentation-generation tool for Haskell
@@ -45,7 +45,6 @@ library
     Documentation.Haddock.Markup
     Documentation.Haddock.Parser
     Documentation.Haddock.Types
-    Documentation.Haddock.Utf8
 
   other-modules:
     Documentation.Haddock.Parser.Util
@@ -71,8 +70,6 @@ test-suite spec
       Documentation.Haddock.Parser.UtilSpec
       Documentation.Haddock.ParserSpec
       Documentation.Haddock.Types
-      Documentation.Haddock.Utf8
-      Documentation.Haddock.Utf8Spec
 
   build-depends:
     , base-compat  ^>= 0.9.3 || ^>= 0.10.0

haddock-library/src/Documentation/Haddock/Utf8.hs

@@ -91,7 +91,6 @@ executable haddock
       Documentation.Haddock.Parser.Monad
       Documentation.Haddock.Types
       Documentation.Haddock.Doc
-      Documentation.Haddock.Utf8
       Documentation.Haddock.Parser.Util
       Documentation.Haddock.Markup