Add hint in faq about anonymous fifo

Instead of always using `-y` and a pipe, it might be better to use an anonymous fifo. That way users get the confirmation dialog with the convenience of a one-liner to generate and apply a manifest.

docs/faq.md

@@ -2,7 +2,7 @@
 
 ### `Error: Asking for confirmation: EOF`
 
-This probably means you have piped configuration into kapp and did not specify `--yes` (`-y`) flag to continue. It's necessary because kapp can no longer ask for confirmation via stdin. Feel free to re-run the command with `--diff-changes` (`-c`) to make sure pending changes are correct.
+This probably means you have piped configuration into kapp and did not specify `--yes` (`-y`) flag to continue. It's necessary because kapp can no longer ask for confirmation via stdin. Feel free to re-run the command with `--diff-changes` (`-c`) to make sure pending changes are correct. Instead of using a pipe you can also use an anonymous fifo keeping stdin free for the confirmation prompt, e.g. `kapp deploy -a app1 -f <(ytt -f config/)`
 
 ---
 ### Where to store app resources (i.e. in which namespace)?