Switch to new pandoc-types and use Text instead of String [API change].

PR #5884.

+ Use pandoc-types 1.20 and texmath 0.12.
+ Text is now used instead of String, with a few exceptions.
+ In the MediaBag module, some of the types using Strings
  were switched to use FilePath instead (not Text).
+ In the Parsing module, new parsers `manyChar`, `many1Char`,
  `manyTillChar`, `many1TillChar`, `many1Till`, `manyUntil`,
  `mantyUntilChar` have been added: these are like their
  unsuffixed counterparts but pack some or all of their output.
+ `glob` in Text.Pandoc.Class still takes String since it seems
  to be intended as an interface to Glob, which uses strings.
  It seems to be used only once in the package, in the EPUB writer,
  so that is not hard to change.

1 files changed, 4 insertions, 2 deletions

diff --git a/src/Text/Pandoc/App/FormatHeuristics.hs b/src/Text/Pandoc/App/FormatHeuristics.hs
index a02d8d15e..25e0a303e 100644
--- a/src/Text/Pandoc/App/FormatHeuristics.hs
+++ b/src/Text/Pandoc/App/FormatHeuristics.hs
@@ -1,4 +1,5 @@
 {-# LANGUAGE NoImplicitPrelude #-}
+{-# LANGUAGE OverloadedStrings #-}
 {- |
    Module      : Text.Pandoc.App.FormatHeuristics
    Copyright   : Copyright (C) 2006-2019 John MacFarlane
@@ -16,10 +17,11 @@ module Text.Pandoc.App.FormatHeuristics
 
 import Prelude
 import Data.Char (toLower)
+import Data.Text (Text)
 import System.FilePath (takeExtension)
 
 -- Determine default format based on file extensions.
-formatFromFilePaths :: [FilePath] -> Maybe String
+formatFromFilePaths :: [FilePath] -> Maybe Text
 formatFromFilePaths [] = Nothing
 formatFromFilePaths (x:xs) =
   case formatFromFilePath x of
@@ -27,7 +29,7 @@ formatFromFilePaths (x:xs) =
     Nothing    -> formatFromFilePaths xs
 
 -- Determine format based on file extension
-formatFromFilePath :: FilePath -> Maybe String
+formatFromFilePath :: FilePath -> Maybe Text
 formatFromFilePath x =
   case takeExtension (map toLower x) of
     ".adoc"     -> Just "asciidoc"