docs/reference/builder: fix USER doc
Docker-DCO-1.1-Signed-off-by: Johan Euphrosine (github: proppy)
@@ -346,7 +346,8 @@ instructions via the Docker client, refer to [*Share Directories via Volumes*](
USER daemon
-The `USER` instruction sets the username or UID to use when running the image.
+The `USER` instruction sets the username or UID to use when running the image
+and for any following `RUN` directives.
## WORKDIR
