Enforce at least one space between list indicator and list text.

src/MdToHTML.hs

@@ -333,6 +333,7 @@ parseUListNested = do
 parseUListLineItem :: ReadP MdToken
 parseUListLineItem = do
   firstChar <- choice (map char ['*', '+', '-'])
+  char ' ' -- At least one space between list indicator and list text.
   skipSpaces
   restOfLine <- manyTill get (void (char '\n') <++ eof)
   let restOfLineParsed = fst $ leftmostLongestParse parseLine restOfLine