Add deprecation notices for error load, unload events

Author: kswedberg

entries/error.xml

@@ -1,6 +1,7 @@
 <?xml version="1.0"?>
 <entry type="method" name="error" return="jQuery">
   <title>.error()</title>
+  <deprecated>1.8</deprecated>
   <desc>Bind an event handler to the "error" JavaScript event.</desc>
   <signature>
     <added>1.0</added>

entries/load-event.xml

@@ -1,6 +1,7 @@
 <?xml version="1.0"?>
 <entry type="method" name="load" return="jQuery">
   <title>.load()</title>
+  <deprecated>1.8</deprecated>
   <desc>Bind an event handler to the "load" JavaScript event.</desc>
   <signature>
     <added>1.0</added>

entries/unload.xml

@@ -1,6 +1,7 @@
 <?xml version="1.0"?>
 <entry type="method" name="unload" return="jQuery">
   <title>.unload()</title>
+  <deprecated>1.8</deprecated>
   <signature>
     <added>1.0</added>
     <argument name="handler(eventObject)" type="Function">