pack-protocol.txt: fix insconsistent spelling of "packfile"

Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pks-t

Documentation/technical/pack-protocol.txt

@@ -502,11 +502,11 @@ MUST NOT send a push-cert command.  When a push-cert command is
 sent, command-list MUST NOT be sent; the commands recorded in the
 push certificate is used instead.
 
-The pack-file MUST NOT be sent if the only command used is 'delete'.
+The packfile MUST NOT be sent if the only command used is 'delete'.
 
-A pack-file MUST be sent if either create or update command is used,
+A packfile MUST be sent if either create or update command is used,
 even if the server already has all the necessary objects.  In this
-case the client MUST send an empty pack-file.   The only time this
+case the client MUST send an empty packfile.   The only time this
 is likely to happen is if the client is creating
 a new branch or a tag that points to an existing obj-id.