tm: extended docs for t_reply()

(cherry picked from commit a221ec3)

modules/tm/README

@@ -1728,7 +1728,7 @@ failure_route[1] {
    deciding if the transaction is complete. In the referred block, you can
    start a new branch which is required for failover of multiple outbound
    flows (RFC 5626). Note that the set of commands which are usable within
-   a branch_failure route is limited to a subset of the failure_rotue
+   a branch_failure route is limited to a subset of the failure_route
    commands including logging, rewriting URI and initiating new branches.
    Any other commands may generate errors or result in unpredictable
    behavior. Note that whenever failure_route is entered, uri is reset to
@@ -1829,6 +1829,17 @@ if (t_newtran()) {
    Sends a stateful reply after a transaction has been established. See
    t_newtran for usage.
 
+   If the code is in the range 300-399 (redirect reply), the current
+   destination set is appended to the reply as Contact headers. The
+   destination set contains the request URI (R-URI), if it is modified
+   compared to the received one, plus the branches added to the request
+   (e.g., after an append_branch() or lookup("location")). If the R-URI
+   was changed but it is not desired to be part of the destination set, it
+   can be reverted using the function revert_uri().
+
+   Custom headers to the reply can be added using append_to_reply()
+   function from textops module.
+
    Meaning of the parameters is as follows:
      * code - Reply code number.
      * reason_phrase - Reason string.

modules/tm/doc/functions.xml

@@ -326,6 +326,19 @@ if (t_newtran()) {
 	    Sends a stateful reply after a transaction has been
 	    established. See <function>t_newtran</function> for usage.
 	</para>
+	<para>
+		If the code is in the range 300-399 (redirect reply), the current
+		destination set is appended to the reply as Contact headers.
+		The destination set contains the request URI (R-URI), if it is
+		modified compared to the received one, plus the branches added to the
+		request (e.g., after an append_branch() or lookup("location")).
+		If the R-URI was changed but it is not desired to be part of the
+		destination set, it can be reverted using the function revert_uri().
+	</para>
+	<para>
+		Custom headers to the reply can be added using append_to_reply()
+		function from textops module.
+	</para>
 	<para>Meaning of the parameters is as follows:</para>
 	<itemizedlist>
 	    <listitem>