Remove the delimiter but keep the corresponding node as text

For unused delimiters such as _ in foo_bar.

Property definitions

markdown2 $ MdInlineParser :: remove_delimiters_keep_node
	# Remove the delimiter but keep the corresponding node as text
	#
	# For unused delimiters such as `_` in `foo_bar`.
	private fun remove_delimiters_keep_node(delim: nullable MdDelimiter) do
		remove_delimiter(delim)
	end
lib/markdown2/markdown_inline_parsing.nit:1039,2--1044,4