[css-scroll-snap][editorial] Add dfn for 're-snap', export some other dfns.

Author: tabatkins

css-scroll-snap-1/Overview.bs

@@ -217,7 +217,7 @@ Scroll Snap Model {#overview}
 =============================
 
     This module defines controls for
-    <dfn lt="scroll snap position" local-lt="snap position">scroll snap positions</dfn>,
+    <dfn export lt="scroll snap position" local-lt="snap position">scroll snap positions</dfn>,
     which are scroll positions that produce particular alignments
     of content within a scroll container.
     Using the 'scroll-snap-type' property on the relevant <a>scroll container</a>,
@@ -240,7 +240,7 @@ Scroll Snap Model {#overview}
     The act of adjusting the scroll position
     of a scroll container’s scrollport
     such that it is aligned to a snap position
-    is called <dfn lt="snap | snapping | snapped">snapping</dfn>,
+    is called <dfn export lt="scroll snap" local-lt="snap">snapping</dfn>,
     and a <a>scroll container</a> is said to be
     <a>snapped</a> to a <a>snap position</a>
     if its scrollport’s scroll position
@@ -397,7 +397,7 @@ Scroll Snap Strictness: the ''scroll-snap-type/none'', ''proximity'', and ''mand
     Otherwise, the box has no <a>scroll snap container</a>,
     and its <a>snap positions</a> do not trigger <a>snapping</a>.
 
-<h4 id="re-snap">
+<h4 id="re-snap" dfn export lt="re-snap">
 Re-snapping After Layout Changes</h4>
 
     If the content or layout of the document changes
@@ -548,7 +548,7 @@ Scroll Snapport: the 'scroll-padding' property {#scroll-padding}
     the user sees a continuous stream of content.
 
     For a <a>scroll snap container</a> this region also defines
-    the <dfn local-lt="snapport">scroll snapport</dfn>--
+    the <dfn export local-lt="snapport">scroll snapport</dfn>--
     the area of the scrollport that is used as the <a>alignment container</a>
     for the <a>scroll snap areas</a> when calculating <a>snap positions</a>.
 
@@ -616,7 +616,7 @@ Scroll Snapping Area: the 'scroll-margin' property {#scroll-margin}
     exactly as the 'margin' property does for its longhands.
 
     Values represent outsets defining the
-    <dfn lt="scroll snap area" local-lt="snap area">scroll snap area</dfn>
+    <dfn export lt="scroll snap area" local-lt="snap area">scroll snap area</dfn>
     that is used for snapping this box to the snapport.
     The <a>scroll snap area</a> is determined by taking the transformed border box,
     finding its rectangular bounding box