Non-breaking spaces in example of Flatten function

Co-authored-by: Ted Thibodeau Jr <[email protected]>

Author: hartig

spec/index.html

@@ -9722,7 +9722,7 @@ <h5>Set Functions</h5>
               and <a href="#defn_Card">Card</a>, which are defined as follows.</p>
             <p><a href="#defn_Flatten">Flatten</a> is a function which is
               used to collapse a sequence of lists into a single list.
-              For example, [(1,&nbsp;2), (3,&nbsp;4)] becomes (1, 2, 3, 4).</p>
+              For example, [(1,&nbsp;2), (3,&nbsp;4)] becomes (1,&nbsp;2,&nbsp;3,&nbsp;4).</p>
             <div class="defn">
               <p><b>Definition: <span id="defn_Flatten">Flatten</span></b></p>
               <p>Let <var>S</var> be a sequence of lists,