New AST nodes for f-string elements (#8835)

Rebase of #6365 authored by @davidszotten.

## Summary

This PR updates the AST structure for an f-string elements.

The main **motivation** behind this change is to have a dedicated node
for the string part of an f-string. Previously, the existing
`ExprStringLiteral` node was used for this purpose which isn't exactly
correct. The `ExprStringLiteral` node should include the quotes as well
in the range but the f-string literal element doesn't include the quote
as it's a specific part within an f-string. For example,

```python
f"foo {x}"
# ^^^^
# This is the literal part of an f-string
```

The introduction of `FStringElement` enum is helpful which represent
either the literal part or the expression part of an f-string.

### Rule Updates

This means that there'll be two nodes representing a string depending on
the context. One for a normal string literal while the other is a string
literal within an f-string. The AST checker is updated to accommodate
this change. The rules which work on string literal are updated to check
on the literal part of f-string as well.

#### Notes

1. The `Expr::is_literal_expr` method would check for
`ExprStringLiteral` and return true if so. But now that we don't
represent the literal part of an f-string using that node, this improves
the method's behavior and confines to the actual expression. We do have
the `FStringElement::is_literal` method.
2. We avoid checking if we're in a f-string context before adding to
`string_type_definitions` because the f-string literal is now a
dedicated node and not part of `Expr`.
3. Annotations cannot use f-string so we avoid changing any rules which
work on annotation and checks for `ExprStringLiteral`.

## Test Plan

- All references of `Expr::StringLiteral` were checked to see if any of
the rules require updating to account for the f-string literal element
node.
- New test cases are added for rules which check against the literal
part of an f-string.
- Check the ecosystem results and ensure it remains unchanged.

## Performance

There's a performance penalty in the parser. The reason for this remains
unknown as it seems that the generated assembly code is now different
for the `__reduce154` function. The reduce function body is just popping
the `ParenthesizedExpr` on top of the stack and pushing it with the new
location.

- The size of `FStringElement` enum is the same as `Expr` which is what
it replaces in `FString::format_spec`
- The size of `FStringExpressionElement` is the same as
`ExprFormattedValue` which is what it replaces

I tried reducing the `Expr` enum from 80 bytes to 72 bytes but it hardly
resulted in any performance gain. The difference can be seen here:
- Original profile: https://share.firefox.dev/3Taa7ES
- Profile after boxing some node fields:
https://share.firefox.dev/3GsNXpD

### Backtracking

I tried backtracking the changes to see if any of the isolated change
produced this regression. The problem here is that the overall change is
so small that there's only a single checkpoint where I can backtrack and
that checkpoint results in the same regression. This checkpoint is to
revert using `Expr` to the `FString::format_spec` field. After this
point, the change would revert back to the original implementation.

## Review process

The review process is similar to #7927. The first set of commits update
the node structure, parser, and related AST files. Then, further commits
update the linter and formatter part to account for the AST change.

---------

Co-authored-by: David Szotten <davidszotten@gmail.com>

crates/ruff_python_ast/src/expression.rs

@@ -23,7 +23,6 @@ pub enum ExpressionRef<'a> {
     YieldFrom(&'a ast::ExprYieldFrom),
     Compare(&'a ast::ExprCompare),
     Call(&'a ast::ExprCall),
-    FormattedValue(&'a ast::ExprFormattedValue),
     FString(&'a ast::ExprFString),
     StringLiteral(&'a ast::ExprStringLiteral),
     BytesLiteral(&'a ast::ExprBytesLiteral),
@@ -67,7 +66,6 @@ impl<'a> From<&'a Expr> for ExpressionRef<'a> {
             Expr::YieldFrom(value) => ExpressionRef::YieldFrom(value),
             Expr::Compare(value) => ExpressionRef::Compare(value),
             Expr::Call(value) => ExpressionRef::Call(value),
-            Expr::FormattedValue(value) => ExpressionRef::FormattedValue(value),
             Expr::FString(value) => ExpressionRef::FString(value),
             Expr::StringLiteral(value) => ExpressionRef::StringLiteral(value),
             Expr::BytesLiteral(value) => ExpressionRef::BytesLiteral(value),
@@ -172,11 +170,6 @@ impl<'a> From<&'a ast::ExprCall> for ExpressionRef<'a> {
         Self::Call(value)
     }
 }
-impl<'a> From<&'a ast::ExprFormattedValue> for ExpressionRef<'a> {
-    fn from(value: &'a ast::ExprFormattedValue) -> Self {
-        Self::FormattedValue(value)
-    }
-}
 impl<'a> From<&'a ast::ExprFString> for ExpressionRef<'a> {
     fn from(value: &'a ast::ExprFString) -> Self {
         Self::FString(value)
@@ -273,7 +266,6 @@ impl<'a> From<ExpressionRef<'a>> for AnyNodeRef<'a> {
             ExpressionRef::YieldFrom(expression) => AnyNodeRef::ExprYieldFrom(expression),
             ExpressionRef::Compare(expression) => AnyNodeRef::ExprCompare(expression),
             ExpressionRef::Call(expression) => AnyNodeRef::ExprCall(expression),
-            ExpressionRef::FormattedValue(expression) => AnyNodeRef::ExprFormattedValue(expression),
             ExpressionRef::FString(expression) => AnyNodeRef::ExprFString(expression),
             ExpressionRef::StringLiteral(expression) => AnyNodeRef::ExprStringLiteral(expression),
             ExpressionRef::BytesLiteral(expression) => AnyNodeRef::ExprBytesLiteral(expression),
@@ -317,7 +309,6 @@ impl Ranged for ExpressionRef<'_> {
             ExpressionRef::YieldFrom(expression) => expression.range(),
             ExpressionRef::Compare(expression) => expression.range(),
             ExpressionRef::Call(expression) => expression.range(),
-            ExpressionRef::FormattedValue(expression) => expression.range(),
             ExpressionRef::FString(expression) => expression.range(),
             ExpressionRef::StringLiteral(expression) => expression.range(),
             ExpressionRef::BytesLiteral(expression) => expression.range(),