Fixed regression in charsInBalancedBrackets.

Introduced by e9d7504.

This regression caused link and image references containing
raw tex not to parse correctly.

Added test.

Closes #2150.

src/Text/Pandoc/Readers/Markdown.hs

@@ -177,9 +177,10 @@ charsInBalancedBrackets openBrackets =
       (char '[' >> charsInBalancedBrackets (openBrackets + 1))
   <|> (char ']' >> charsInBalancedBrackets (openBrackets - 1))
   <|> ((  (() <$ code)
-     <|> (() <$ escapedChar')
+     <|> (() <$ (escapedChar'))
      <|> (newline >> notFollowedBy blankline)
      <|> skipMany1 (noneOf "[]`\n\\")
+     <|> (() <$ count 1 (oneOf "`\\"))
       ) >> charsInBalancedBrackets openBrackets)
 
 --

tests/markdown-reader-more.native

@@ -150,6 +150,8 @@
 ,Para [Link [Str "link"] ("/hi(there)","")]
 ,Para [Link [Str "link"] ("/hithere)","")]
 ,Para [Link [Str "linky"] ("hi_(there_(nested))","")]
+,Header 2 ("backslashes-in-link-references",[],[]) [Str "Backslashes",Space,Str "in",Space,Str "link",Space,Str "references"]
+,Para [Link [Str "*",RawInline (Format "tex") "\\a"] ("b","")]
 ,Header 2 ("reference-link-fallbacks",[],[]) [Str "Reference",Space,Str "link",Space,Str "fallbacks"]
 ,Para [Str "[",Emph [Str "not",Space,Str "a",Space,Str "link"],Str "]",Space,Str "[",Emph [Str "nope"],Str "]\8230"]
 ,Header 2 ("reference-link-followed-by-a-citation",[],[]) [Str "Reference",Space,Str "link",Space,Str "followed",Space,Str "by",Space,Str "a",Space,Str "citation"]

tests/markdown-reader-more.txt

@@ -258,6 +258,10 @@ Empty cells
 
 [linky]: hi_(there_(nested))
 
+## Backslashes in link references
+
+[\*\a](b)
+
 ## Reference link fallbacks
 
 [*not a link*] [*nope*]...