[css-position-3] Add hyphens to dfns.

Author: fantasai

css-position-3/Overview.bs

@@ -220,7 +220,7 @@ Choosing A Positioning Scheme: 'position' property</h2>
 		and does not affect the size or position of any other box,
 		except insofar as it increases the [=scrollable overflow area=] of its ancestors.
 		This [=positioning scheme=] is called
-		<dfn export dfn lt="relative position|relatively position" local-lt="relative|relatively">relative positioning</dfn>.
+		<dfn export dfn lt="relative position|relatively-positioned" local-lt="relative|relatively">relative positioning</dfn>.
 
 	<dt><dfn>sticky</dfn>
 	<dd>
@@ -232,7 +232,7 @@ Choosing A Positioning Scheme: 'position' property</h2>
 		to try to keep the box in view within its [=containing block=]
 		as the user scrolls.
 		This [=positioning scheme=] is called
-		<dfn export dfn lt="sticky position" local-lt="sticky">sticky positioning</dfn>.
+		<dfn export dfn lt="sticky position|sticky-positioned" local-lt="sticky">sticky positioning</dfn>.
 
 	<dt><dfn>absolute</dfn>
 	<dd>
@@ -246,7 +246,7 @@ Choosing A Positioning Scheme: 'position' property</h2>
 		It can overlap in-flow siblings
 		or other [=absolutely positioned=] elements.
 		This [=positioning scheme=] is called
-		<dfn export dfn lt="absolute position|absolutely position" local-lt="absolute|absolutely">absolute positioning</dfn>.
+		<dfn export dfn lt="absolute position|absolutely-positioned" local-lt="absolute|absolutely">absolute positioning</dfn>.
 
 	<dt><dfn>fixed</dfn>
 	<dd>
@@ -257,7 +257,7 @@ Choosing A Positioning Scheme: 'position' property</h2>
 		it does not move when the document is scrolled,
 		and is replicated on every page when it is paginated.
 		This [=positioning scheme=] is called
-		<dfn export dfn lt="fixed position" local-lt="fixed">fixed positioning</dfn>
+		<dfn export dfn lt="fixed position|fixed-positioned" local-lt="fixed">fixed positioning</dfn>
 		and is considered a subset of [=absolute positioning=].
 
 		<div class="example">