[css-fonts-5] Fix typo in tech() function (w3c#7086)

Author: drott

css-fonts-5/Overview.bs

@@ -357,7 +357,7 @@ according to section [[css-syntax#parse-comma-separated-list-of-component-values
 Then each component value is parsed according to this grammar:
 
 
-<pre><<url>> [ format(<<font-format>>)]? [ techn( <<font-tech>>#)]? | local(<<font-face-name>>)</pre>
+<pre><<url>> [ format(<<font-format>>)]? [ tech( <<font-tech>>#)]? | local(<<font-face-name>>)</pre>
 
 <pre class="prod"><dfn id="font-format-values">&lt;font-format&gt;</dfn>
 	 = [<<string>> | collection | embedded-opentype | opentype