[css-images-3][editorial] Use radial- rather than rg-

This makes it more sensible to re-use the terms in e.g. <basic-shape>.

Author: fantasai

css-images-3/Overview.bs

@@ -509,14 +509,14 @@ Radial Gradients: the ''radial-gradient()'' notation {#radial-gradients}
 		<<radial-gradient()>> = radial-gradient( [ <<radial-gradient-syntax>> ] )
 
 		<dfn>&lt;radial-gradient-syntax></dfn> =
-			[ <<rg-ending-shape>> || <<rg-size>> ]? [ at <<position>> ]? ,
+			[ <<radial-shape>> || <<radial-size>> ]? [ at <<position>> ]? ,
 			<<color-stop-list>>
 
-		<dfn>&lt;rg-size></dfn> = <<rg-extent-keyword>> | <<length [0,∞]>> | <<length-percentage [0,∞]>>{2}
+		<dfn>&lt;radial-size></dfn> = <<radial-extent>> | <<length [0,∞]>> | <<length-percentage [0,∞]>>{2}
 
-		<dfn>&lt;rg-extent-keyword></dfn> = closest-corner | closest-side | farthest-corner | farthest-side
+		<dfn>&lt;radial-extent></dfn> = closest-corner | closest-side | farthest-corner | farthest-side
 
-		<dfn>&lt;rg-ending-shape></dfn> = circle | ellipse
+		<dfn>&lt;radial-shape></dfn> = circle | ellipse
 	</pre>
 
 	<div class=example>
@@ -546,16 +546,16 @@ Radial Gradients: the ''radial-gradient()'' notation {#radial-gradients}
 			If this argument is omitted,
 			it defaults to ''<position>/center''.
 
-		<dt><dfn><<rg-ending-shape>></dfn>
+		<dt><dfn><<radial-shape>></dfn>
 		<dd>
-			Can be either <dfn value for="<rg-ending-shape>">circle</dfn> or <dfn value for="<rg-ending-shape>">ellipse</dfn>;
+			Can be either <dfn value for="<radial-shape>">circle</dfn> or <dfn value for="<radial-shape>">ellipse</dfn>;
 			determines whether the gradient's <a>ending shape</a> is a circle or an ellipse, respectively.
-			If <<rg-ending-shape>> is omitted,
+			If <<radial-shape>> is omitted,
 			the <a>ending shape</a> defaults to a circle
-			if the <<rg-size>> is a single <<length>>,
+			if the <<radial-size>> is a single <<length>>,
 			and to an ellipse otherwise.
 
-		<dt><dfn><<rg-size>></dfn>
+		<dt><dfn><<radial-size>></dfn>
 		<dd>
 			Determines the size of the gradient's <a>ending shape</a>.
 			If omitted it defaults to ''farthest-corner''.
@@ -567,9 +567,9 @@ Radial Gradients: the ''radial-gradient()'' notation {#radial-gradients}
 			If the ending-shape is an ellipse,
 			its axises are aligned with the horizontal and vertical axises.
 
-			Both ''circle'' and ''ellipse'' gradients accept the following <<rg-extent-keyword>> values:
+			Both ''circle'' and ''ellipse'' gradients accept the following <<radial-extent>> values:
 
-			<dl dfn-for="<rg-extent-keyword>, radial-gradient(), repeating-radial-gradient()">
+			<dl dfn-for="<radial-extent>, radial-gradient(), repeating-radial-gradient()">
 				<dt><dfn>closest-side</dfn>
 				<dd>
 					The <a>ending shape</a> is sized so that
@@ -597,11 +597,11 @@ Radial Gradients: the ''radial-gradient()'' notation {#radial-gradients}
 					the <a>ending shape</a> is given the same aspect ratio it would have if ''farthest-side'' were specified.
 			</dl>
 
-			If <<rg-ending-shape>> is specified as ''circle'' or is omitted,
-			the <<rg-size>> may be given explicitly as:
+			If <<radial-shape>> is specified as ''circle'' or is omitted,
+			the <<radial-size>> may be given explicitly as:
 
 			<dl>
-				<dt><dfn for="<rg-size>, radial-gradient(), repeating-radial-gradient()">&lt;length [0,∞]></dfn>
+				<dt><dfn for="<radial-size>, radial-gradient(), repeating-radial-gradient()">&lt;length [0,∞]></dfn>
 				<dd>
 					Gives the radius of the circle explicitly.
 					Negative values are invalid.
@@ -615,11 +615,11 @@ Radial Gradients: the ''radial-gradient()'' notation {#radial-gradients}
 
 			</dl>
 
-			If <<rg-ending-shape>> is specified as ''ellipse'' or is omitted,
-			<<rg-size>> may instead be given explicitly as:
+			If <<radial-shape>> is specified as ''ellipse'' or is omitted,
+			<<radial-size>> may instead be given explicitly as:
 
 			<dl>
-				<dt><dfn for="<rg-size>, radial-gradient(), repeating-radial-gradient()"><<length-percentage [0,∞]>>{2}</dfn>
+				<dt><dfn for="<radial-size>, radial-gradient(), repeating-radial-gradient()"><<length-percentage [0,∞]>>{2}</dfn>
 				<dd>
 					Gives the size of the ellipse explicitly.
 					The first value represents the horizontal radius,
@@ -637,7 +637,7 @@ Radial Gradients: the ''radial-gradient()'' notation {#radial-gradients}
 			radial-gradient() = radial-gradient(
 			  [ [ circle               || <<length [0,∞]>> ]                          [ at <<position>> ]? , |
 			    [ ellipse              || <<length-percentage [0,∞]>>{2} ]            [ at <<position>> ]? , |
-			    [ [ circle | ellipse ] || <<rg-extent-keyword>> ]                     [ at <<position>> ]? , |
+			    [ [ circle | ellipse ] || <<radial-extent>> ]                     [ at <<position>> ]? , |
 			    at <<position>></span> ,
 			  ]?
 			  <<color-stop-list>>