Correct case in constraint network description

Author: Bartosz Białas

html/3_002e3.xhtml

@@ -2013,7 +2013,7 @@ to <math xmlns="http://www.w3.org/1998/Math/MathML">
 45, and <math xmlns="http://www.w3.org/1998/Math/MathML">
   <mi>v</mi>
 </math> awakens the adder, which sets <math xmlns="http://www.w3.org/1998/Math/MathML">
-  <mi>f</mi>
+  <mi>F</mi>
 </math> to 77.
 </p>
 <a id="Using-the-constraint-system"></a>
@@ -2714,4 +2714,4 @@ Next: <a href="3_002e4.xhtml#g_t3_002e4" accesskey="n" rel="next">3.4</a>, Prev:
 
 </section><span class="bottom jump" title="Jump to bottom"><a href="#pagebottom" accesskey="b">⇣</a></span><a id="pagebottom"></a>
 </body>
-</html>
+</html>