Add hint for setting up gpg-agent socket

On my system (Linux Mint) `gpgconf --list-dirs agent-ssh-socket` does return all dirs and not only the one for agent-ssh-socket hence `ssh-add -L` was failing. This is a hint for other people to troubleshoot this behaviour.

1 files changed, 1 insertions, 1 deletions

diff --git a/README.md b/README.md
index d492ffa..bb92758 100644
--- a/README.md
+++ b/README.md
@@ -1696,7 +1696,7 @@ And reload the SSH daemon (e.g., `sudo service sshd reload`).
 
 - If you still receive the error, `sign_and_send_pubkey: signing failed: agent refused operation` - check `~/.gnupg/gpg-agent.conf` to make sure the path to `pinentry` is correct.
 
-- If you receive the error, `Error connecting to agent: No such file or directory` from `ssh-add -L`, the UNIX file socket that the agent uses for communication with other processes may not be set up correctly. On Debian, try `export SSH_AUTH_SOCK="/run/user/$UID/gnupg/S.gpg-agent.ssh"`
+- If you receive the error, `Error connecting to agent: No such file or directory` from `ssh-add -L`, the UNIX file socket that the agent uses for communication with other processes may not be set up correctly. On Debian, try `export SSH_AUTH_SOCK="/run/user/$UID/gnupg/S.gpg-agent.ssh"`. Also see that `gpgconf --list-dirs agent-ssh-socket` is returning single path, to existing `S.gpg-agent.ssh` socket.
 
 - If you receive the error, `Permission denied (publickey)`, increase ssh verbosity with the `-v` flag and ensure the public key from the card is being offered: `Offering public key: RSA SHA256:abcdefg... cardno:00060123456`. If it is, ensure you are connecting as the right user on the target system, rather than as the user on the local system. Otherwise, be sure `IdentitiesOnly` is not [enabled](https://github.com/FiloSottile/whosthere#how-do-i-stop-it) for this host.