Remove AstNode and AnyNode (#15479)

While looking into potential AST optimizations, I noticed the `AstNode`
trait and `AnyNode` type aren't used anywhere in Ruff or Red Knot. It
looks like they might be historical artifacts of previous ways of
consuming AST nodes?

- `AstNode::cast`, `AstNode::cast_ref`, and `AstNode::can_cast` are not
used anywhere.
- Since `cast_ref` isn't needed anymore, the `Ref` associated type isn't
either.

This is a pure refactoring, with no intended behavior changes.

crates/ruff_python_formatter/src/statement/stmt_global.rs

@@ -1,5 +1,4 @@
 use ruff_formatter::{format_args, write};
-use ruff_python_ast::AstNode;
 use ruff_python_ast::StmtGlobal;
 
 use crate::comments::SourceComment;
@@ -14,7 +13,7 @@ impl FormatNodeRule<StmtGlobal> for FormatStmtGlobal {
         // Join the `global` names, breaking across continuation lines if necessary, unless the
         // `global` statement has a trailing comment, in which case, breaking the names would
         // move the comment "off" of the `global` statement.
-        if f.context().comments().has_trailing(item.as_any_node_ref()) {
+        if f.context().comments().has_trailing(item) {
             let joined = format_with(|f| {
                 f.join_with(format_args![token(","), space()])
                     .entries(item.names.iter().formatted())

crates/ruff_python_formatter/src/statement/stmt_import_from.rs

@@ -1,5 +1,4 @@
 use ruff_formatter::write;
-use ruff_python_ast::AstNode;
 use ruff_python_ast::StmtImportFrom;
 use ruff_text_size::Ranged;
 
@@ -62,7 +61,7 @@ impl FormatNodeRule<StmtImportFrom> for FormatStmtImportFrom {
         // )
         // ```
         let comments = f.context().comments().clone();
-        let parenthesized_comments = comments.dangling(item.as_any_node_ref());
+        let parenthesized_comments = comments.dangling(item);
 
         if parenthesized_comments.is_empty() {
             parenthesize_if_expands(&names).fmt(f)

crates/ruff_python_formatter/src/statement/stmt_nonlocal.rs

@@ -1,5 +1,4 @@
 use ruff_formatter::{format_args, write};
-use ruff_python_ast::AstNode;
 use ruff_python_ast::StmtNonlocal;
 
 use crate::comments::SourceComment;
@@ -14,7 +13,7 @@ impl FormatNodeRule<StmtNonlocal> for FormatStmtNonlocal {
         // Join the `nonlocal` names, breaking across continuation lines if necessary, unless the
         // `nonlocal` statement has a trailing comment, in which case, breaking the names would
         // move the comment "off" of the `nonlocal` statement.
-        if f.context().comments().has_trailing(item.as_any_node_ref()) {
+        if f.context().comments().has_trailing(item) {
             let joined = format_with(|f| {
                 f.join_with(format_args![token(","), space()])
                     .entries(item.names.iter().formatted())

crates/ruff_python_formatter/src/statement/stmt_while.rs

@@ -1,5 +1,4 @@
 use ruff_formatter::{format_args, write};
-use ruff_python_ast::AstNode;
 use ruff_python_ast::{Stmt, StmtWhile};
 use ruff_text_size::Ranged;
 
@@ -22,7 +21,7 @@ impl FormatNodeRule<StmtWhile> for FormatStmtWhile {
         } = item;
 
         let comments = f.context().comments().clone();
-        let dangling_comments = comments.dangling(item.as_any_node_ref());
+        let dangling_comments = comments.dangling(item);
 
         let body_start = body.first().map_or(test.end(), Stmt::start);
         let or_else_comments_start =

crates/ruff_python_formatter/src/statement/stmt_with.rs

@@ -1,6 +1,5 @@
 use ruff_formatter::{format_args, write, FormatContext, FormatError};
-use ruff_python_ast::StmtWith;
-use ruff_python_ast::{AstNode, WithItem};
+use ruff_python_ast::{StmtWith, WithItem};
 use ruff_python_trivia::{SimpleTokenKind, SimpleTokenizer};
 use ruff_text_size::{Ranged, TextRange};
 
@@ -36,7 +35,7 @@ impl FormatNodeRule<StmtWith> for FormatStmtWith {
         //     ...
         // ```
         let comments = f.context().comments().clone();
-        let dangling_comments = comments.dangling(with_stmt.as_any_node_ref());
+        let dangling_comments = comments.dangling(with_stmt);
         let partition_point = dangling_comments.partition_point(|comment| {
             with_stmt
                 .items