Improve ease of understanding of the documentation

While, strictly speaking, the file basename (without extension)
does not matter, supply one, as the wildcard keeps tripping up
contributors. Use the new name but (still) the older directory
until the code looks in the new directory.

docs/admin/03_psql.rst

@@ -30,7 +30,7 @@ random, password. You can generate one using the pwgen utility if you like::
 Configure BiscuIT to use PostgreSQL
 -----------------------------------
 
-Fill in the configuration under `/etc/biscuit/*.toml`::
+Fill in the configuration under `/etc/biscuit/aleksis.toml`::
 
   [default.database]
   host = "localhost"