refactor: use progress_message internal interpolation

Co-authored-by: Richard Levasseur <rlevasseur@google.com>

python/private/py_wheel.bzl

diff --git a/python/private/py_wheel.bzl b/python/private/py_wheel.bzl
index 8b9460f..e7a03c1 100644
--- a/python/private/py_wheel.bzl
+++ b/python/private/py_wheel.bzl
@@ -428,7 +428,7 @@
                         outputs = [link],
                         arguments = [args],
                         executable = linker,
-                        progress_message = "Linking {} to {}".format(file.path, link.path),
+                        progress_message = "Linking %{input} to %{output}",
                         mnemonic = "PyWheelLink",
                     )
                     filtered.append(link)