[css-snappoints] Adding definition of snap position, and rephrasing in terms of that. Removing resolved issues. No functional changes.

Author: ChumpChief

css-snappoints/Overview.src.html

@@ -162,11 +162,15 @@ <h2 id="definitions">Definitions</h2>
         <dt><dfn export>scroll container</dfn>
         <dd>
             An element which provides a scrolling user interface as described in [[!CSS21]], particularly in the section on overflow.
+
+        <dt><dfn export>snap position</dfn>
+        <dd>
+            For a scroll container, a particular value for its scroll offset is a snap position if when scrolled to that offset the visual viewport of the scroll container would align with a descendent element in the manner specified by the scroll snap properties.
     </dl>
 
 <h2 id="scroll-snap-type">Scroll Snap Types: the 'scroll-snap-type' property</h2>
 
-    The ''scroll-snap-type'' property is used to define how strictly snap points are enforced on the <a>scroll container</a>, if any are present. It defines how and when snap points are enforced on the visual viewport of the scroll container it is applied to in order to adjust scroll offset.  It intentionally does not specify nor mandate any precise animations or physics used to enforce those snap points; this is left up to the user agent.
+    The ''scroll-snap-type'' property is used to define how strictly a <a>scroll container's</a> visual viewport should rest on <a>snap positions</a>.  It intentionally does not specify nor mandate any precise animations or physics used to enforce those snap points; this is left up to the user agent.
 
     <pre class='propdef'>
     Name: scroll-snap-type
@@ -183,25 +187,17 @@ <h2 id="scroll-snap-type">Scroll Snap Types: the 'scroll-snap-type' property</h2
     <dl dfn-type="value" dfn-for="scroll-snap-type">
         <dt><dfn>none</dfn>
         <dd>
-            The visual viewport of this <a>scroll container</a> must ignore snap points, if any, when scrolled.
+            The visual viewport of this <a>scroll container</a> must ignore snap positions.
 
         <dt><dfn>mandatory</dfn>
         <dd>
-            The visual viewport of this <a>scroll container</a> is guaranteed to rest on a snap point when there are no active scrolling operations.  That is, it must come to rest on a snap point at the termination of a scroll, if a valid, reachable snap point exists (if no valid, reachable snap point exists then no snapping occurs).  If the content changes such that the visual viewport would no longer rest on a snap point (e.g. content is added, moved, deleted, resized), the scroll offset must be modified to maintain this guarantee.
+            The visual viewport of this <a>scroll container</a> is guaranteed to rest on a snap position when there are no active scrolling operations.  That is, it must come to rest on a snap position at the termination of a scroll, if a valid, reachable snap position exists.  If no valid, reachable snap position exists then no snapping occurs.  If the content changes such that the visual viewport would no longer rest on a snap position (e.g. content is added, moved, deleted, resized), the scroll offset must be modified to maintain this guarantee.
 
         <dt><dfn>proximity</dfn>
         <dd>
-            The visual viewport of this <a>scroll container</a> may come to rest on a snap point at the termination of a scroll at the discretion of the UA given the parameters of the scroll.  If the content changes such that the visual viewport would no longer rest on a snap point (e.g. content is added, moved, deleted, resized), the scroll offset may be modified to maintain this guarantee.
+            The visual viewport of this <a>scroll container</a> may come to rest on a snap position at the termination of a scroll at the discretion of the UA given the parameters of the scroll.  If the content changes such that the visual viewport would no longer rest on a snap position (e.g. content is added, moved, deleted, resized), the scroll offset may be modified to maintain this guarantee.
     </dl>
 
-    <div class="issue">
-        Describe the guarantee as an invariant for better clarity.  Include edge case behavior such as mandatory snap points when there is no satisfiable snap point.
-    </div>
-
-    <div class="issue">
-        Should there be a way to specify that either end of the scrollable content should have a snap point?
-    </div>
-
 <h2 id="scroll-snap-destination">Scroll Snap Destination: the 'scroll-snap-destination' property</h2>
 
     The 'scroll-snap-destination' property is used to define the x and y coordinate within the <a>scroll container's</a> visual viewport