Docs: more indexing for freeze_tell

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 23e06f91d1142d59b73a428d7dbe4c3f9c6c090c..5122c97fbe5b2ae2c6d8d23cae6fd55c0645406b 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -16045,6 +16045,7 @@ search the file multiple times for non-existent users, and also cause delay.
 
 .option freeze_tell main "string list, comma separated" unset
 .cindex "freezing messages" "sending a message when freezing"
+.cindex "frozen messages" "sending a message when freezing"
 On encountering certain errors, or when configured to do so in a system filter,
 ACL, or special router, Exim freezes a message. This means that no further
 delivery attempts take place until an administrator thaws the message, or the