Add myself and revised PR to changelog entry

Signed-off-by: Marek Kubica <marek@tarides.com>

doc/changes/6035.md

@@ -1,3 +1,3 @@
 - `dune exec`: support syntax like `%{bin:program}`. This can appear anywhere
   in the command line, so things like `dune exec time %{bin:program}` now work.
-  (#6035, fixes #2691, @emillon)
+  (#6035, #8474, fixes #2691, @emillon, @Leonidas-from-XIV)