Change headline of technical/send-pack-pipeline.txt to not confuse its content with content from git-send-pack.txt

Signed-off-by: Thomas Ackermann <th.acker@arcor.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/technical/send-pack-pipeline.txt

@@ -1,5 +1,5 @@
-git-send-pack
-=============
+Git-send-pack internals
+=======================
 
 Overall operation
 -----------------