[css-cascade-5] possible typo (w3c#6167)

* possible typo

* Update css-cascade-5/Overview.bs

Co-authored-by: Tab Atkins Jr <jackalmage@gmail.com>

Author: himorin

css-cascade-5/Overview.bs

@@ -1233,7 +1233,7 @@ Declaring Cascade Layers: the ''@layer'' rule</h4>
 	that represents its <dfn>layer name</dfn>.
 	If the [=layer name=] matches that of a [=cascade layer=]
 	already defined within this [=origin=] and [=context=]
-	(and same [=layer=] scope, see [[#nested-layers]]),
+	(and the same [=layer=] scope, see [[#nested-layers]]),
 	then its style rules are assigned to that same [=cascade layer=].
 	Otherwise, or if no <<layer-ident>> is provided,
 	a new [=cascade layer=] is created.