siputils/doc: updated pcv documentation [skip ci]

- Updated documentation to reflect the changes to the $pcv pseudo-var
  and the sip_p_charging_vector() function.

(cherry picked from commit 05a30ed53fc5657a2d86e1c1bdb9277571a8d17e)

src/modules/siputils/doc/siputils.xml

@@ -95,6 +95,14 @@
 		</address>
 	    	</editor>
 
+		<editor>
+		<firstname>Eik</firstname>
+		<surname>Rentzow</surname>
+		<address>
+		    <email>[email protected]</email>
+		</address>
+    	</editor>
+
 	</authorgroup>
 	<copyright>
 		<year>2008</year>

src/modules/siputils/doc/siputils_admin.xml

@@ -1237,7 +1237,33 @@ if(is_first_hop("1")) { ... }
 		<para>
 			Manage the P-Charging-Vector header (RFC7315). The flags can be:
 			'r' - remove; 'g' - generate; 'f' - force (remove + generate).
+			Once a new PCV has been generated by 'g' or 'f' the PCV cannot be changed again.
+			The icid-generated-at parameter of a generated PCV will be set to
+			the sending interface.IP address.
 		</para>
+		<para>
+			Return Codes: 
+		</para>
+			<itemizedlist>
+				<listitem><para>
+					<emphasis>1</emphasis> - Nothing was done.
+				</para></listitem>
+				<listitem><para>
+					<emphasis>(2</emphasis> - <emphasis>intentionally left out)</emphasis>
+				</para></listitem>
+				<listitem><para>
+					<emphasis>3</emphasis> - P-Charging-Vector header has been newly generated.
+				</para></listitem>
+				<listitem><para>
+					<emphasis>4</emphasis> - P-Charging-Vector header has been deleted.
+				</para></listitem>
+				<listitem><para>
+					<emphasis>5</emphasis> - P-Charging-Vector header has been replaced or inserted after deletion.
+				</para></listitem>
+				<listitem><para>
+					<emphasis>negative</emphasis> - Any error occured during execution.
+				</para></listitem>
+			</itemizedlist>
 		<para>
 		This function can be used from ANY_ROUTE.
 		</para>
@@ -1469,6 +1495,32 @@ if (!hdr_date_check("10")) {
 						term-ioi field (see RFC7315 section 5.6)
 					</para>
 			</section>
+			<section id="siputils.v.pcv_status">
+					<title><varname>$pcv(status)</varname></title>
+					<para>
+						Returns whether the PCV header was successfully parsed, deleted, 
+						newly generated or other.
+					<itemizedlist>
+						<listitem><para>
+							<emphasis>0</emphasis> - No P-Charging-Vector header in message.
+						</para></listitem>
+						<listitem><para>
+							<emphasis>1</emphasis> - P-Charging-Vector header in message and parsed successfully.
+						</para></listitem>
+						<listitem><para>
+							<emphasis>2</emphasis> - P-Charging-Vector is present, but has no valid
+														<emphasis>icid-value</emphasis> parameter.
+						</para></listitem>
+						<listitem><para>
+							<emphasis>3</emphasis> - P-Charging-Vector header has been newly generated or replaced.
+						</para></listitem>
+						<listitem><para>
+							<emphasis>4</emphasis> - P-Charging-Vector header has been deleted.
+						</para></listitem>
+					</itemizedlist>
+					Negative values indicate an internal error during the parsing process.
+					</para>
+			</section>
 	</section>
 
 </chapter>