feat: support target table alias in update statement

[jonahgao]

Which issue does this PR close?

N/A.

Support statements like UPDATE foo AS f .

Rationale for this change

When an alias is provided, it completely hides the actual name of the table. For example, given UPDATE foo AS f, the remainder of the UPDATE statement must refer to this table as f not foo.

Ref: PostgreSQL UPDATE SQL Commands

What changes are included in this PR?

If there is an alias for the target table, use it to properly qualify the column names from the target table.

Are these changes tested?

Yes

Are there any user-facing changes?

No

[alamb]

Looks good to me @jonahgao -- thank you for the contribution (again). These improvements are really appreciated.

You might be interested in #8008 which is also related to qualified names.

[jonahgao]

Looks good to me @jonahgao -- thank you for the contribution (again). These improvements are really appreciated.

You might be interested in #8008 which is also related to qualified names.

Thank you for your review @alamb .
I will pay attention to this issue and hope to be helpful.