clarify run image resolution during restore phase

Signed-off-by: Pavel Busko <pavel.busko@sap.com>

platform.md

@@ -536,7 +536,7 @@ Usage:
   - MUST record the digest reference to the provided `<build-image>` in `<analyzed>`
   - MUST copy the OCI manifest and config file for `<build-image>` to `<kaniko-dir>/cache`
 - The lifecycle:
-  - MUST resolve `run-image.reference` to a digest reference in `<analyzed>` if not present
+  - MUST [resolve mirrors](#run-image-resolution) for the `run-image.reference` in `<analyzed>` and resolve it to a digest reference
   - MUST populate `run-image.target` data in `<analyzed>` if not present
   - **If** `<analyzed>` has `run-image.extend = true`, the lifecycle:
     - MUST download from the registry and save in OCI layout format the `run-image` in `<analyzed>` to `<kaniko-dir>/cache`