trivial: fix broken link markdown

In-page link was [text][url] instead of [text](url).

Signed-off-by: Tim Pepper <[email protected]>

Author: Tim Pepper

keps/sig-apps/0753-sidecarcontainers.md

@@ -105,7 +105,7 @@ shutdown have met several times and are in sync regarding these features
 interoperability.
 
 The details about this dependency is explained in the [graduation criteria
-section][#graduation-criteria].
+section](#graduation-criteria).
 
 ## Motivation