[css-backgrounds-4] Define background-repeat|position longhands with a logical property group

Author: cdoublev

css-backgrounds-4/Overview.bs

@@ -48,6 +48,7 @@ Tiling Images: the 'background-repeat-x', 'background-repeat-y', 'background-rep
 		Percentages: N/A
 		Computed value: as specified
 		Animation type: discrete
+		Logical property group: background-repeat
 	</pre>
 
 	<pre class="prod">
@@ -262,6 +263,7 @@ Background Positioning Longhands: the 'background-position-x', 'background-posit
 		Percentages: refer to width of background positioning area <em>minus</em> width of background image
 		Computed value: A list, each item consisting of: an offset given as a computed <<length-percentage>> value, plus an origin keyword
 		Animation type: repeatable list
+		Logical property group: background-position
 	</pre>
 
 	This property specifies the background position's horizontal component.
@@ -276,6 +278,7 @@ Background Positioning Longhands: the 'background-position-x', 'background-posit
 		Percentages: refer to height of background positioning area <em>minus</em> height of background image
 		Computed value: A list, each item consisting of: an offset given as a computed <<length-percentage>> value, plus an origin keyword
 		Animation type: repeatable list
+		Logical property group: background-position
 	</pre>
 
 	This property specifies the background position's vertical component.
@@ -290,6 +293,7 @@ Background Positioning Longhands: the 'background-position-x', 'background-posit
 		Percentages: refer to inline-size of background positioning area <em>minus</em> inline-size of background image
 		Computed value: A list, each item consisting of: an offset given as a computed <<length-percentage>> value, plus an origin keyword
 		Animation type: repeatable list
+		Logical property group: background-position
 	</pre>
 
 	This property specifies the background position's inline-axis component.
@@ -304,6 +308,7 @@ Background Positioning Longhands: the 'background-position-x', 'background-posit
 		Percentages: refer to size of background positioning area <em>minus</em> size of background image
 		Computed value: A list, each item consisting of: an offset given as a computed <<length-percentage>> value, plus an origin keyword
 		Animation type: repeatable list
+		Logical property group: background-position
 	</pre>
 
 	This property specifies the background position's block-axis component.