Docs: add index entry

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index a0eb53c58e3d12c662a6a11cdc9446aae78d96f5..546a944b6fbbdfe628caaa5c673d39bae588fba8 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -28999,6 +28999,7 @@ This modifier puts a value into one of the ACL variables (see section
 
 
 .vitem &*udpsend*&&~=&~<&'parameters'&>
+.cindex "UDP communications"
 This modifier sends a UDP packet, for purposes such as statistics
 collection or behaviour monitoring. The parameters are expanded, and
 the result of the expansion must be a colon-separated list consisting