API documentation references DisplayLayer, which is not public

[winstliu]

text-buffer/src/display-marker-layer.coffee

Lines 6 to 7 in 3d8e692

	# Public: *Experimental:* A container for a related set of markers at the
	# {DisplayLayer} level. Wraps an underlying {MarkerLayer} on the {TextBuffer}.

leads to https://atom.io/docs/api/v1.21.1/DisplayLayer, which is a 404.