Fix complaints about playground local reference.

Author: gkellogg

index.html

@@ -533,7 +533,7 @@ <h2>Expansion</h2>
         <button data-selects="expanded">Expanded (Result)</button>
         <button data-selects="statements">Statements</button>
         <button data-selects="turtle">Turtle</button>
-        <a class="playground" target="_blank" href="#">PG</a>
+        <a class="playground" target="_blank" href="">PG</a>
       </div>
       <pre class="compacted selected" data-transform="updateExample">
       <!--
@@ -599,7 +599,7 @@ <h2>Expansion</h2>
         <button data-selects="expanded">Expanded (Result)</button>
         <button data-selects="statements">Statements</button>
         <button data-selects="turtle">Turtle</button>
-        <a class="playground" target="_blank" href="#">PG</a>
+        <a class="playground" target="_blank" href="">PG</a>
       </div>
       <pre class="compacted input selected nohighlight" data-transform="updateExample">
       <!--
@@ -774,7 +774,7 @@ <h2>Compaction</h2>
            data-context="#sample-document-context"
            data-compact
            target="_blank"
-           href="#">PG</a>
+           href="">PG</a>
       </div>
       <pre class="result compacted selected nohighlight" data-transform="updateExample"
            data-result-for="Expanded sample document"
@@ -857,7 +857,7 @@ <h2>Flattening</h2>
            data-result-for="#json-ld-document-in-compact-form"
            data-flatten
            target="_blank"
-           href="#">PG</a>
+           href="">PG</a>
       </div>
       <pre class="original result selected nohighlight" data-transform="updateExample"
            data-result-for="JSON-LD document in compact form"
@@ -903,7 +903,7 @@ <h2>Flattening</h2>
            data-context="#json-ld-document-in-compact-form"
            data-flatten
            target="_blank"
-            href="#">PG</a>
+            href="">PG</a>
       </div>
       <pre class="result selected nohighlight" data-transform="updateExample"
            data-result-for="JSON-LD document in compact form"