[css-overflow] Editorial tweak to use correct terminology

Author: frivoal

css-display-3/Overview.bs

@@ -1060,7 +1060,7 @@ Appendix A: Glossary</h2>
 			without further precision as to the type of formatting context or how to do so.
 			This operation is not applicable to
 			non-atomic inline-level boxes
-			nor to boxes with a layout-internal display-type.
+			nor to boxes with a layout-internal display type.
 			Specifications that invoke this
 			must either exclude such boxes,
 			or to blockify them first.