Create a new bracket for an image

Property definitions

markdown2 $ MdBracket :: image
	# Create a new bracket for an image
	init image(node: MdText, index: Int, column: Int, prev: nullable MdBracket, prev_delimiter: nullable MdDelimiter) do
		init(node, index, column, true, prev, prev_delimiter)
	end
lib/markdown2/markdown_inline_parsing.nit:1223,2--1226,4