Made <color> and <1d-image> exclusive alternatives

Author: SebastianZ

css-backgrounds-4/Overview.bs

@@ -185,7 +185,7 @@ Painting Area: the 'background-clip' property</h3>
 
 	<pre class=propdef>
 	Name: border-top-color, border-right-color, border-bottom-color, border-left-color
-	Value: <<color>> || <<1d-image>>
+	Value: <<color>> | <<1d-image>>
 	Initial: currentcolor
 	Applies to: all elements
 	Inherited: no
@@ -196,7 +196,7 @@ Painting Area: the 'background-clip' property</h3>
 
 	<pre class="propdef shorthand">
 	Name: border-color
-	Value: [ <<color>> || <<1d-image>> ]{1,4}
+	Value: [ <<color>> | <<1d-image>> ]{1,4}
 	</pre>
 
 	These properties set the foreground color of the border specified

css-ui-4/Overview.bs

@@ -287,7 +287,7 @@ Animation type: by computed value
 
 <pre class="propdef">
 Name: outline-color
-Value: [ <<color>> || <<1d-image>> ] | invert
+Value: [ <<color>> | <<1d-image>> ] | invert
 Initial: invert
 Applies to: all elements
 Inherited: no