## Summary
This change continues to resolve#16071 (and continues the work started
in #16162). Specifically, this PR changes the code in the parser so that
it uses the `OperatorPrecedence` struct from `ruff_python_ast` instead
of its own version. This is part of an effort to get rid of the
redundant definitions of `OperatorPrecedence` throughout the codebase.
Note that this PR only makes this change for `ruff_python_parser` -- we
still want to make a similar change for the formatter (namely the
`OperatorPrecedence` defined in the expression part of the formatter,
the pattern one is different). I separated the work to keep the PRs
small and easily reviewable.
## Test Plan
Because this is an internal change, I didn't add any additional tests.
Existing tests do pass.
## Summary
This change follows up on the bug-fix requested in #16747 --
`ruff_python_ast::OperatorPrecedence` had an enum variant, `BitXorOr`,
which which gave the same precedence to the `|` and `^` operators. This
goes against [Python's documentation for operator
precedence](https://docs.python.org/3/reference/expressions.html#operator-precedence),
so this PR changes the code so that it's correct.
This is part of the overall effort to unify redundant definitions of
`OperatorPrecedence` throughout the codebase (#16071)
## Test Plan
Because this is an internal change, I only ran existing tests to ensure
nothing was broken.
## Summary
This change begins to resolve#16071 by moving the `OperatorPrecedence`
structs from the `ruff_python_linter` crate into `ruff_python_ast`. This
PR also implements `precedence()` methods on the `Expr` and `ExprRef`
enums.
## Test Plan
Since this change mainly shifts existing logic, I didn't add any
additional tests. Existing tests do pass.
