DOC: missing http-send-name-header keyword in keyword table

This one was in the doc but not in the keyword matrix.
diff --git a/doc/configuration.txt b/doc/configuration.txt
index 7aff1e6d..ba8057f 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -1143,6 +1143,7 @@
 http-check send-state                     X          -         X         X
 http-request                              -          X         X         X
 http-response                             -          X         X         X
+http-send-name-header                     -          -         X         X
 id                                        -          X         X         X
 ignore-persist                            -          X         X         X
 log                                  (*)  X          X         X         X