Tweak the reference combinator section wording. Allow the host language to define other syntaxes than just idref and id selectors.

Author: tabatkins

selectors4/Overview.html

@@ -1994,9 +1994,10 @@ <h3 id=id-selectors><span class=secno>6.7. </span> ID selectors</h3>
    attributes differently, but the same restriction applies.
 
   <p>An ID-typed attribute of a document language allows authors to assign an
-   identifier to one element instance in the document tree. An ID selector
-   contains a &quot;number sign&quot; (U+0023, <code>#</code>) immediately
-   followed by the ID value, which must be an CSS <a
+   identifier to one element instance in the document tree. An <dfn
+   id=id-selector>ID selector</dfn> contains a &quot;number sign&quot;
+   (U+0023, <code>#</code>) immediately followed by the ID value, which must
+   be an CSS <a
    href="http://www.w3.org/TR/CSS21/syndata.html#value-def-identifier">identifiers</a>.
    An ID selector represents an element instance that has an identifier that
    matches the identifier in the ID selector.
@@ -2228,8 +2229,8 @@ <h3 id=scope-pseudo><span class=secno>7.5. </span> The contextual reference
    parent element of a <a
    href="http://www.whatwg.org/specs/web-apps/current-work/multipage/semantics.html#the-style-element">scoped
    <code>&lt;style></code> element</a> in <a href="#HTML5"
-   rel=biblioentry>[HTML5]<!--{{HTML5}}--></a>, which is typically used to
-   "scope" a selector so that it only matches within a subtree.
+   rel=biblioentry>[HTML5]<!--{{HTML5}}--></a>, which is used to "scope" a
+   selector so that it only matches within a subtree.
 
   <p> If no contextual reference element set is given, <code>:scope</code> is
    equivalent to <code>:root</code>. Specifications intending for this
@@ -3285,16 +3286,17 @@ <h3 id=general-sibling-combinators><span class=secno>14.4. </span>
   <h3 id=idref-combinators><span class=secno>14.5. </span> Reference
    combinators</h3>
 
-  <p>The IDREF combinator consists of two slashes with an indetervening <a
+  <p> The <dfn id=reference-combinator>reference combinator</dfn> consists of
+   two slashes with an indetervening <a
    href="http://www.w3.org/TR/css3-namespace/#css-qnames">CSS qualified
    name</a>, and separates two compound selectors, e.g. <code>A /attr/
-   B</code>. The elements represented by the two compound seletors are
-   related in that an element represented by the first compound selector has
-   an ID-reference to the element represented by the second compound
-   selector. The ID reference can be given as either an IDREF or a fragment
-   URL: the reference is valid as long as the value of the attribute named in
-   the combinator consists of either the ID alone or a hash mark (#) followed
-   by the ID. Attribute matching for reference combinators follow the same
+   B</code>. The element represented by the first compound selector
+   explicitly references the element represented by the second compound
+   selector. Unless the host language defines a different syntax for
+   expressing this relationship, this relationship is considered to exist if
+   the value of the specified attribute on the first element is an IDREF or
+   an <a href="#id-selector"><i>ID selector</i></a> referencing the second
+   element. Attribute matching for reference combinators follow the same
    rules as for <a
    href="http://www.w3.org/TR/css3-selectors/#attribute-selectors">attribute
    selectors</a>.

selectors4/Overview.src.html

@@ -1323,7 +1323,7 @@ <h3 id=id-selectors>
 
   <p>An ID-typed attribute of a document language allows authors to
   assign an identifier to one element instance in the document tree. An
-  ID selector contains a &quot;number sign&quot; (U+0023,
+  <dfn>ID selector</dfn> contains a &quot;number sign&quot; (U+0023,
   <code>#</code>) immediately followed by the ID value, which must be an
   CSS <a href="http://www.w3.org/TR/CSS21/syndata.html#value-def-identifier">identifiers</a>.
   An ID selector represents an element instance that has an
@@ -2496,18 +2496,20 @@ <h3 id=general-sibling-combinators>
 <h3 id=idref-combinators>
 Reference combinators</h3>
 
-  <p>The IDREF combinator consists of two slashes with an indetervening
-    <a href="http://www.w3.org/TR/css3-namespace/#css-qnames">CSS qualified
-    name</a>, and separates two compound selectors, e.g. <code>A /attr/ B</code>.
-    The elements represented by the two compound seletors are related in
-    that an element represented by the first compound selector has an
-    ID-reference to the element represented by the second compound selector.
-    The ID reference can be given as either an IDREF or a fragment URL: the
-    reference is valid as long as the value of the attribute named in the
-    combinator consists of either the ID alone or a hash mark (#) followed
-    by the ID. Attribute matching for reference combinators follow the same rules
-    as for <a href="http://www.w3.org/TR/css3-selectors/#attribute-selectors">attribute
-    selectors</a>.
+  <p>
+    The <dfn>reference combinator</dfn> consists of two slashes 
+    with an indetervening <a href="http://www.w3.org/TR/css3-namespace/#css-qnames">CSS qualified name</a>, 
+    and separates two compound selectors, 
+    e.g. <code>A /attr/ B</code>. 
+    The element represented by the first compound selector 
+    explicitly references 
+    the element represented by the second compound selector. 
+    Unless the host language defines a different syntax for expressing this relationship,
+    this relationship is considered to exist if
+    the value of the specified attribute on the first element is an IDREF or an <i>ID selector</i>
+    referencing the second element.
+    
+    Attribute matching for reference combinators follow the same rules as for <a href="http://www.w3.org/TR/css3-selectors/#attribute-selectors">attribute selectors</a>.
 
   <div class="example">
     <p>The following example highlights an <code>&lt;input&gt;</code> element