dfs() does not generate the expected result

[snovik75]

This code:

tree = parse_one("select a from b")

for n in tree.dsf():
    print(n, type(n))

outputs

SELECT a FROM b <class 'sqlglot.expressions.Select'>
a <class 'sqlglot.expressions.Column'>
a <class 'sqlglot.expressions.Identifier'>
FROM b <class 'sqlglot.expressions.From'>
b <class 'sqlglot.expressions.Table'>
b <class 'sqlglot.expressions.Identifier'>

There are 2 clear issues here:

1. the tree itself comes as the first element while it should come last
2. Identifier should always come before Column or Table because it is deeper in the tree (i.e. the order is wrong)

[georgesittas]

Relevant Slack discussion for context: https://tobiko-data.slack.com/archives/C0448SFS3PF/p1744101733575189.