Return the char at the current input index, or \0

Property definitions

markdown2 $ MdInlineParser :: peek
	# Return the char at the current input index, or `\0`
	private fun peek: Char do
		if index < input.length then
			return input.chars[index]
		end
		return '\0'
	end
lib/markdown2/markdown_inline_parsing.nit:299,2--305,4