Get the position of the next non-space character.

Property definitions

markdown :: markdown $ Text :: skip_spaces
	# Get the position of the next non-space character.
	private fun skip_spaces(start: Int): Int do
		var pos = start
		while pos > -1 and pos < length and (self[pos] == ' ' or self[pos] == '\n') do
			pos += 1
		end
		if pos < length then return pos
		return -1
	end
lib/markdown/markdown.nit:2335,2--2343,4