Use reference to space characters instead of undefined "white space".

Author: gkellogg

index.html

@@ -8500,8 +8500,8 @@ <h3>Graph Containers</h3>
       and other text which complicate extracting the JSON-LD content from a <a data-cite="HTML52/semantics-scripting.html#data-block">data blocks</a>.
       JSON-LD places further restrictions on the contents of
       <a data-cite="HTML52/semantics-scripting.html#the-script-element">script elements</a> containing JSON-LD.</p>
-    <p>A JSON-LD script element MAY begin with an optional <em>comment-open</em> surrounded by any amount of white space,
-      followed by valid JSON and ending with an optional <em>comment-close</em> surrounded by any amount of white space.
+    <p>A JSON-LD script element MAY begin with an optional <em>comment-open</em> surrounded by any amount of <a data-cite="HTML52/infrastructure.html#space-characters">space characters</a>,
+      followed by valid JSON and ending with an optional <em>comment-close</em> surrounded by any amount of <a data-cite="HTML52/infrastructure.html#space-characters">space characters</a>.
       Any content within the JSON content which can be confused with a <em>comment-open</em>, <em>script-open</em>,
       <em>comment-close</em>, or <em>script-close</em> MUST be escaped using a REVERSE SOLIDUS (<code>\</code>) character
       as follows:</p>