remove wrong pin-priority is optional remark (Closes: #574944)

debian/changelog

@@ -36,6 +36,7 @@ apt (0.7.26) UNRELEASED; urgency=low
       Thanks to Osamu Aoki for pointing it out! (Closes: #567669)
     - fix a=sid vs. n=sid typo, thanks Ansgar Burchardt!
     - origin can be used to match a hostname (Closes: #352667)
+    - remove wrong pin-priority is optional remark (Closes: #574944)
   * apt-pkg/deb/dpkgpm.cc:
     - fix error message construction in OpenLog()
     - if available store the Commandline in the history

doc/apt_preferences.5.xml

@@ -476,10 +476,6 @@ distribution.</para>
 <para>Each record in the APT preferences file can optionally begin with
 one or more lines beginning with the word <literal>Explanation:</literal>.
 This provides a place for comments.</para>
-
-<para>The <literal>Pin-Priority:</literal> line in each APT preferences record is
-optional.  If omitted, APT assigns a priority of 1 less than the last value
-specified on a line beginning with <literal>Pin-Priority: release ...</literal>.</para>
 </refsect2>
 </refsect1>