Add clarifying text

Insert sentence in introduction to explain what % placeholders mean

diff --git a/doc/sphinx/mes2doc.py b/doc/sphinx/mes2doc.py
index eb7f412bffc85dc3f8b96e6d596af7d3cd5a2904..6b0461f6bb7c8721e49f903f7fc6c41b5b9579cc 100755 (executable)
--- a/doc/sphinx/mes2doc.py
+++ b/doc/sphinx/mes2doc.py
@@ -80,9 +80,12 @@ Consortium (ISC).
 
 This is the reference guide for Kea version |release|.
 Links to the most up-to-date version of this document (in PDF, HTML,
-and plain text formats), along with other documents for
+and plain text formats), along with other useful information about
 Kea, can be found in ISC's `Knowledgebase <https://kb.isc.org/docs/kea-administrator-reference-manual>`_.
 
+Please note that in the messages below, the percent sign ("%") followed by a number is
+used to indicate a placeholder for data that is provided by the Kea code during its operation.
+
 
 .. toctree::
    :numbered: