Fix a deprecated int-to-char comparison in markdown

similar to #10833, only happens with windows line endings

Author: tkelman

base/markdown/Common/block.jl

@@ -19,7 +19,7 @@ function paragraph(stream::IO, md::MD)
     while !eof(stream)
         char = read(stream, Char)
         if char == '\n' || char == '\r'
-            char == '\r' && peek(stream) == '\n' && read(stream, Char)
+            char == '\r' && Char(peek(stream)) == '\n' && read(stream, Char)
             if prev_char == '\\'
                 write(buffer, '\n')
             elseif blankline(stream) || parse(stream, md, breaking = true)