Another fix for synopsis of 'apt-get install'.

doc/apt-get.8.xml

@@ -62,14 +62,16 @@
          <arg>dselect-upgrade</arg>
          <arg>install 
 			 <arg choice="plain" rep="repeat"><replaceable>pkg</replaceable>
-				<group choice='opt'>
-					<arg>
-						=<replaceable>pkg_version_number</replaceable>
-					</arg>
-					<arg>
-						/<replaceable>target_release_name</replaceable>
-					</arg>
-				</group>
+				<arg>
+					<group choice='req'>
+						<arg choice='plain'>
+							=<replaceable>pkg_version_number</replaceable>
+						</arg>
+						<arg choice='plain'>
+							/<replaceable>target_release_name</replaceable>
+						</arg>
+					</group>
+				</arg>
 			 </arg>
 	     </arg>
          <arg>remove <arg choice="plain" rep="repeat"><replaceable>pkg</replaceable></arg></arg>