Muse reader: allow footnotes to start with empty line

A space character was required after footnote marker, now newline is allowed.

src/Text/Pandoc/Readers/Muse.hs

@@ -492,9 +492,10 @@ amuseNoteBlockUntil :: PandocMonad m
                     -> MuseParser m (F Blocks, a)
 amuseNoteBlockUntil end = try $ do
   guardEnabled Ext_amuse
-  ref <- noteMarker <* spaceChar
+  ref <- noteMarker
   pos <- getPosition
-  (content, e) <- allowPara $ listItemContentsUntil (sourceColumn pos - 1) (fail "x") end
+  void spaceChar <|> lookAhead eol
+  (content, e) <- allowPara $ listItemContentsUntil (sourceColumn pos) (fail "x") end
   addNote ref pos content
   return (mempty, e)
 

test/Tests/Readers/Muse.hs

@@ -797,6 +797,23 @@ tests =
                       , "baz"
                       ] =?>
             para (str "Foo" <> note (lineBlock ["bar"])) <> para (str "baz")
+
+          , "Footnote starting with empty line" =:
+            T.unlines [ "Foo[1]"
+                      , ""
+                      , "[1]" -- No space character after note marker
+                      , ""
+                      , "    Bar"
+                      ] =?>
+            para (str "Foo" <> note (para $ text "Bar"))
+          , "Indentation in footnote starting with empty line" =:
+            T.unlines [ "Foo[1]"
+                      , ""
+                      , "[1]" -- No space character after note marker
+                      , ""
+                      , "   Bar"
+                      ] =?>
+            para (str "Foo" <> note mempty) <> blockQuote (para $ text "Bar")
           , test emacsMuse "Emacs multiparagraph footnotes"
             (T.unlines
               [ "First footnote reference[1] and second footnote reference[2]."