Delete type-ignore node

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## Summary

This PR removes the type ignore node from the AST because our parser doesn't support it, and just having it around is confusing.

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## Test Plan

`cargo build`

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crates/ruff_python_formatter/src/other/mod.rs

@@ -9,5 +9,4 @@ pub(crate) mod except_handler_except_handler;
 pub(crate) mod identifier;
 pub(crate) mod keyword;
 pub(crate) mod match_case;
-pub(crate) mod type_ignore_type_ignore;
 pub(crate) mod with_item;

crates/ruff_python_formatter/src/other/type_ignore_type_ignore.rs

@@ -1,12 +0,0 @@
-use crate::{not_yet_implemented, FormatNodeRule, PyFormatter};
-use ruff_formatter::{write, Buffer, FormatResult};
-use ruff_python_ast::TypeIgnoreTypeIgnore;
-
-#[derive(Default)]
-pub struct FormatTypeIgnoreTypeIgnore;
-
-impl FormatNodeRule<TypeIgnoreTypeIgnore> for FormatTypeIgnoreTypeIgnore {
-    fn fmt_fields(&self, item: &TypeIgnoreTypeIgnore, f: &mut PyFormatter) -> FormatResult<()> {
-        write!(f, [not_yet_implemented(item)])
-    }
-}