doc/git-config: add unit for http.lowSpeedLimit

Add the unit (bytes per second) for http.lowSpeedLimit
in the documentation.

Signed-off-by: Corentin Garcia <corenting@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: corenting

Documentation/config/http.txt

@@ -246,8 +246,9 @@ significantly since the entire buffer is allocated even for small
 pushes.
 
 http.lowSpeedLimit, http.lowSpeedTime::
-	If the HTTP transfer speed is less than 'http.lowSpeedLimit'
-	for longer than 'http.lowSpeedTime' seconds, the transfer is aborted.
+	If the HTTP transfer speed, in bytes per second, is less than
+	'http.lowSpeedLimit' for longer than 'http.lowSpeedTime' seconds,
+	the transfer is aborted.
 	Can be overridden by the `GIT_HTTP_LOW_SPEED_LIMIT` and
 	`GIT_HTTP_LOW_SPEED_TIME` environment variables.