Prevent non-existent help handbook from populating the main handbook table of contents.

tderadio3/src/tderadio.desktop

@@ -3,7 +3,13 @@ Encoding=UTF-8
 Type=Application
 Exec=tderadio -caption "%c" %i %m
 Icon=tderadio
-DocPath=tderadio/index.html
+# Restore the following key and remove this comment when a help handbook
+# is written. Disabling this key prevents populating the main handbook
+# table of contents with a non-existent document, which results in a
+# main handbook error message of
+# 'There is no documentation available for /xyz/index.html.'
+# Also disable this key when there exists only a useless template handbook.
+# DocPath=tderadio/index.html
 Comment=Audio player for Internet and AM/FM Radio
 Comment[de]=
 Terminal=false