Update selectors.html

Correct small typo in selectors.html

manual/Types/selectors.html

@@ -714,7 +714,7 @@
     element that represents a <a href="../using.html#path">path-like structure</a> for finding
     custom interface implementations.</p>
 
-    <p>All attributes of a <code>&lt;modified&gt;</code> selector an be set with
+    <p>All attributes of a <code>&lt;modified&gt;</code> selector can be set with
     nested <code>&lt;param/&gt;</code> tags. Additional values can be set
     with <code>&lt;param/&gt;</code> tags according to the rules below.</p>