[internal] Move Linter OperatorPrecedence into ruff_python_ast crate (#16162)

## 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.

crates/ruff_python_ast/src/nodes.rs

@@ -18,7 +18,8 @@ use crate::{
     name::Name,
     str::{Quote, TripleQuotes},
     str_prefix::{AnyStringPrefix, ByteStringPrefix, FStringPrefix, StringLiteralPrefix},
-    ExceptHandler, Expr, FStringElement, LiteralExpressionRef, Pattern, Stmt, TypeParam,
+    ExceptHandler, Expr, ExprRef, FStringElement, LiteralExpressionRef, OperatorPrecedence,
+    Pattern, Stmt, TypeParam,
 };
 
 /// See also [Module](https://docs.python.org/3/library/ast.html#ast.Module)
@@ -365,6 +366,17 @@ impl Expr {
             _ => None,
         }
     }
+
+    /// Return the [`OperatorPrecedence`] of this expression
+    pub fn precedence(&self) -> OperatorPrecedence {
+        OperatorPrecedence::from(self)
+    }
+}
+
+impl ExprRef<'_> {
+    pub fn precedence(&self) -> OperatorPrecedence {
+        OperatorPrecedence::from(self)
+    }
 }
 
 /// An AST node used to represent a IPython escape command at the expression level.