[css-values-3][css-values] Fix incorrect dfn-for attribute for resolution type definitions.

Author: dbaron

css-values-3/Overview.bs

@@ -1306,7 +1306,7 @@ Resolution Units: the <<resolution>> type and ''dpi'', ''dpcm'', ''dppx'' units<
 	Resolution units are <a>dimensions</a> denoted by <dfn id="resolution-value">&lt;resolution></dfn>.
 	The resolution unit identifiers are:
 
-	<dl export dfn-type=value dfn-for="<frequency>">
+	<dl export dfn-type=value dfn-for="<resolution>">
 		<dt><dfn id="dpi">dpi</dfn>
 		<dd>Dots per inch.
 

css-values/Overview.bs

@@ -1365,7 +1365,7 @@ Resolution Units: the <<resolution>> type and ''dpi'', ''dpcm'', ''dppx'' units<
 	Resolution units are <a>dimensions</a> denoted by <dfn id="resolution-value">&lt;resolution></dfn>.
 	The resolution unit identifiers are:
 
-	<dl export dfn-type=value dfn-for="<frequency>">
+	<dl export dfn-type=value dfn-for="<resolution>">
 		<dt><dfn id="dpi">dpi</dfn>
 		<dd>Dots per inch.