Remove obsolete RelaxedPolyRec extension (#6487)

src/Text/Pandoc/Readers/Markdown.hs

@@ -1,4 +1,3 @@
-{-# LANGUAGE RelaxedPolyRec      #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE TupleSections       #-}
 {-# LANGUAGE OverloadedStrings   #-}

src/Text/Pandoc/Readers/MediaWiki.hs

@@ -1,6 +1,4 @@
 {-# LANGUAGE OverloadedStrings #-}
-{-# LANGUAGE RelaxedPolyRec    #-}
--- RelaxedPolyRec needed for inlinesBetween on GHC < 7
 {- |
    Module      : Text.Pandoc.Readers.MediaWiki
    Copyright   : Copyright (C) 2012-2020 John MacFarlane

src/Text/Pandoc/Readers/Metadata.hs

@@ -1,4 +1,3 @@
-{-# LANGUAGE RelaxedPolyRec      #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE OverloadedStrings   #-}
 {- |

src/Text/Pandoc/Readers/TWiki.hs

@@ -1,7 +1,5 @@
 {-# LANGUAGE FlexibleContexts  #-}
 {-# LANGUAGE OverloadedStrings #-}
-{-# LANGUAGE RelaxedPolyRec    #-}
--- RelaxedPolyRec needed for inlinesBetween on GHC < 7
 {- |
    Module      : Text.Pandoc.Readers.TWiki
    Copyright   : Copyright (C) 2014 Alexander Sulfrian

src/Text/Pandoc/Readers/TikiWiki.hs

@@ -1,6 +1,5 @@
 {-# LANGUAGE FlexibleContexts  #-}
 {-# LANGUAGE OverloadedStrings #-}
-{-# LANGUAGE RelaxedPolyRec    #-}
 
 {- |
    Module      : Text.Pandoc.Readers.TikiWiki