apt: Minor typo in 'apt' man page (closes: #743657)

doc/apt.8.xml

@@ -143,7 +143,7 @@
 
  <refsect1><title>Differences to &apt-get;</title>
  <para>The <command>apt</command> command is meant to be pleasant for
- end users and does not need to be backward compatilbe like
+ end users and does not need to be backward compatible like
  &apt-get;. Therefore some options are different:
  
  <itemizedlist>