RelNotes/2.24.0: fix self-contradictory note

As per Wikipedia, "In current technical usage, for one to state that a
feature is deprecated is merely a recommendation against using it."  It
is thus contradictory to claim that something is not "officially
deprecated" and then to immediately state that we are both discouraging
its use and pointing people elsewhere.

Signed-off-by: Elijah Newren <newren@gmail.com>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/RelNotes/2.24.0.txt

@@ -6,10 +6,9 @@ Updates since v2.23
 
 Backward compatibility note
 
- * Although it is not officially deprecated, "filter-branch" is
-   showing its age and alternatives are available.  From this release,
-   we started to discourage its uses and hint people about
-   filter-repo.
+ * "filter-branch" is showing its age and alternatives are available.
+   From this release, we started to discourage its use and hint
+   people about filter-repo.
 
 UI, Workflows & Features