[css-color-5][editorial] grammar

Author: svgeesus

css-color-5/Overview.bs

@@ -828,7 +828,7 @@ but they all follow a common structure:
 * The origin color and the relative color need not use the same color function.
 * If an [=origin color=] is specified,
 	the remaining arguments can either be specified directly, as normal,
-	be specified as a <dfn>channel keyword</dfn> 
+	or be specified as a <dfn>channel keyword</dfn> 
 	referring to one of the channels of the [=origin color=].
 	[=Math functions=] can also use these keywords
 	to do dynamic modifications of the [=origin color's=] channels.