comment: dist -> ctr

Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>

cmd/ctr/fetch.go

@@ -31,9 +31,8 @@ This command ensures that containerd has all the necessary resources to build
 an image's rootfs and convert the configuration to a runtime format supported
 by containerd.
 
-This command uses the same syntax, of remote and object, as 'dist
-fetch-object'. We may want to make this nicer, but agnostism is preferred for
-the moment.
+This command uses the same syntax, of remote and object, as 'ctr fetch-object'.
+We may want to make this nicer, but agnostism is preferred for the moment.
 
 Right now, the responsibility of the daemon and the cli aren't quite clear. Do
 not use this implementation as a guide. The end goal should be having metadata,