Error output is going to `stdout` rather than `stderr`

[coolaj86]

The error goes out to the sql file instead of the error log.

echo "foobar" | sqlfmt > formatted.sql 2> error.log

formatted.sql:

at or near "bananagram": syntax error

error.log:

I think this is the reason for #68.

[maddyblue]

Concur!