Add ascii_identifiers as a supported extension for markdown.

This fixes a regression in 2.8.

src/Text/Pandoc/Extensions.hs

@@ -374,9 +374,21 @@ getDefaultExtensions "opml"            = pandocExtensions -- affects notes
 getDefaultExtensions _                 = extensionsFromList
                                           [Ext_auto_identifiers]
 
-allMarkdownExtensions :: Extensions
-allMarkdownExtensions =
-  pandocExtensions <>
+
+-- | Get all valid extensions for a format. This is used
+-- mainly in checking format specifications for validity.
+getAllExtensions :: T.Text -> Extensions
+getAllExtensions f = universalExtensions <> getAll f
+ where
+  autoIdExtensions           = extensionsFromList
+    [ Ext_auto_identifiers
+    , Ext_gfm_auto_identifiers
+    , Ext_ascii_identifiers
+    ]
+  universalExtensions        = extensionsFromList
+    [ Ext_east_asian_line_breaks ]
+  allMarkdownExtensions =
+    pandocExtensions <> autoIdExtensions <>
       extensionsFromList
        [ Ext_old_dashes
        , Ext_angle_brackets_escapable
@@ -400,20 +412,6 @@ allMarkdownExtensions =
        , Ext_smart
        , Ext_literate_haskell
        ]
-
-
--- | Get all valid extensions for a format. This is used
--- mainly in checking format specifications for validity.
-getAllExtensions :: T.Text -> Extensions
-getAllExtensions f = universalExtensions <> getAll f
- where
-  autoIdExtensions           = extensionsFromList
-    [ Ext_auto_identifiers
-    , Ext_gfm_auto_identifiers
-    , Ext_ascii_identifiers
-    ]
-  universalExtensions        = extensionsFromList
-    [ Ext_east_asian_line_breaks ]
   getAll "markdown_strict"   = allMarkdownExtensions
   getAll "markdown_phpextra" = allMarkdownExtensions
   getAll "markdown_mmd"      = allMarkdownExtensions