[css-page] Fix typo

Author: lahmatiy

css-page/Overview.bs

@@ -685,7 +685,7 @@ the <a href="https://www.w3.org/TR/CSS21/selector.html">Selectors</a> module:
 <ul>
 	<li>Count the number of page type names (= <var>f</var>)
 		<p class="note">
-			Given the syntax of page seletors, <var>f</var> can only ever be 0 or 1.
+			Given the syntax of page selectors, <var>f</var> can only ever be 0 or 1.
 	<li>Count the number of ':first' or ':blank' pseudo-classes (= <var>g</var>)
 	<li>Count the number of ':left' or ':right' pseudo-classes (= <var>h</var>)
 </ul>