dev-manual: Fixed typo for AUTOREV.

(From yocto-docs rev: a1fd83f0aeaab95693335150f330bbc7c5af18f8)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/dev-manual/dev-manual-common-tasks.xml

@@ -5434,7 +5434,7 @@
             Then, you can add the following to your
             <filename>local.conf</filename>:
             <literallayout class='monospaced'>
-     SRCREV_pn-&lt;PN&gt; = "${AUTOREF}"
+     SRCREV_pn-&lt;PN&gt; = "${AUTOREV}"
             </literallayout>
             <ulink url='&YOCTO_DOCS_REF_URL;#var-PN'><filename>PN</filename></ulink>
             is the name of the recipe for which you want to enable automatic source