[css-values-5][editorial] Export some terms

Author: tabatkins

css-values-5/Overview.bs

@@ -844,7 +844,7 @@ Interpolation Progress Calculations: the ''progress()'' notation</h2>
 <h2 id="mixing">
 Weighted Average Notations: the *-mix() family</h2>
 
-	Several <dfn>mix notations</dfn> in CSS
+	Several <dfn export>mix notations</dfn> in CSS
 	allow representing the weighted average of a set of values.
 	These [=functional notations=] follow the syntactic pattern:
 
@@ -854,7 +854,7 @@ Weighted Average Notations: the *-mix() family</h2>
 
 	where the <var>options</var> can provide type-specific mixing options,
 	and each <var>value</var> and optional <<percentage>> pair in the argument list
-	is a <dfn>mix item</dfn> representing
+	is a <dfn export>mix item</dfn> representing
 	an input to the mix and its weight in the average.
 
 	The [=mix notations=] in CSS include:
@@ -879,7 +879,7 @@ Normalizing Mix Percentages</h3>
 	or else assigned to a “none” type value as defined by the specific [=mix notation=].
 
 	<div algorithm>
-		To <dfn>normalize mix percentages</dfn>
+		To <dfn export>normalize mix percentages</dfn>
 		given
 		* a [=/list=] of [=mix items=] |items|
 			(a value and optional percentage, each between 0% and 100% if specified)