Fix typo in upgrade_v2.2 document

doc/upgrade_v2.2.html

@@ -62,7 +62,7 @@ make it always go to the very start instead:</p>
 <pre>  extraKeys: {"Home": "goLineStart"}</pre>
 
 <p>Similarly, <code>Enter</code> is bound
-to <code>"newLineAndIndent"</code> by default. You can bind it to
+to <code>"newlineAndIndent"</code> by default. You can bind it to
 something else to get different behavior. To disable special handling
 completely and only get a newline character inserted, you can bind it
 to <code>false</code>:</p>