Fix preparation anchor

howto/yubikey.md

@@ -753,7 +753,7 @@ itself. We obviously can't recover this if we lose the YubiKey, so
 let's exercise that disaster recovery by making a new key, completely
 from the backups.
 
- 1. first, go through the [preparation](#preparation) steps above, namely setting
+ 1. first, go through the [preparation](#install-software-and-preparation) steps above, namely setting
     the CCID mode, disabling NFC, setting a PIN and so on
 
  1. create a fresh new GnuPG home: