docs: recognisable -> recognizable

Most of the docs is US English, let's stick to that.

Reviewed-by: Eric Engestrom <eric@engestrom.ch>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6864>
diff --git a/docs/download.rst b/docs/download.rst
index 7596fc2..a7c7ea3 100644
--- a/docs/download.rst
+++ b/docs/download.rst
@@ -18,7 +18,7 @@
 patch after that).
 
 When a new release is coming, release candidates (betas) may be found in
-the same directory, and are recognisable by the
+the same directory, and are recognizable by the
 ``mesa-Y.N.P-rcX.tar.gz`` filename.
 
 Unpacking