Split Constant to individual literal nodes (#8064)

## Summary

This PR splits the `Constant` enum as individual literal nodes. It
introduces the following new nodes for each variant:
* `ExprStringLiteral`
* `ExprBytesLiteral`
* `ExprNumberLiteral`
* `ExprBooleanLiteral`
* `ExprNoneLiteral`
* `ExprEllipsisLiteral`

The main motivation behind this refactor is to introduce the new AST
node for implicit string concatenation in the coming PR. The elements of
that node will be either a string literal, bytes literal or a f-string
which can be implemented using an enum. This means that a string or
bytes literal cannot be represented by `Constant::Str` /
`Constant::Bytes` which creates an inconsistency.

This PR avoids that inconsistency by splitting the constant nodes into
it's own literal nodes, literal being the more appropriate naming
convention from a static analysis tool perspective.

This also makes working with literals in the linter and formatter much
more ergonomic like, for example, if one would want to check if this is
a string literal, it can be done easily using
`Expr::is_string_literal_expr` or matching against `Expr::StringLiteral`
as oppose to matching against the `ExprConstant` and enum `Constant`. A
few AST helper methods can be simplified as well which will be done in a
follow-up PR.

This introduces a new `Expr::is_literal_expr` method which is the same
as `Expr::is_constant_expr`. There are also intermediary changes related
to implicit string concatenation which are quiet less. This is done so
as to avoid having a huge PR which this already is.

## Test Plan

1. Verify and update all of the existing snapshots (parser, visitor)
2. Verify that the ecosystem check output remains **unchanged** for both
the linter and formatter

### Formatter ecosystem check

#### `main`

| project | similarity index | total files | changed files |

|----------------|------------------:|------------------:|------------------:|
| cpython | 0.75803 | 1799 | 1647 |
| django | 0.99983 | 2772 | 34 |
| home-assistant | 0.99953 | 10596 | 186 |
| poetry | 0.99891 | 317 | 17 |
| transformers | 0.99966 | 2657 | 330 |
| twine | 1.00000 | 33 | 0 |
| typeshed | 0.99978 | 3669 | 20 |
| warehouse | 0.99977 | 654 | 13 |
| zulip | 0.99970 | 1459 | 22 |

#### `dhruv/constant-to-literal`

| project | similarity index | total files | changed files |

|----------------|------------------:|------------------:|------------------:|
| cpython | 0.75803 | 1799 | 1647 |
| django | 0.99983 | 2772 | 34 |
| home-assistant | 0.99953 | 10596 | 186 |
| poetry | 0.99891 | 317 | 17 |
| transformers | 0.99966 | 2657 | 330 |
| twine | 1.00000 | 33 | 0 |
| typeshed | 0.99978 | 3669 | 20 |
| warehouse | 0.99977 | 654 | 13 |
| zulip | 0.99970 | 1459 | 22 |

crates/ruff_python_formatter/src/expression/binary_like.rs

@@ -5,8 +5,7 @@ use smallvec::SmallVec;
 
 use ruff_formatter::write;
 use ruff_python_ast::{
-    Constant, Expr, ExprAttribute, ExprBinOp, ExprBoolOp, ExprCompare, ExprConstant, ExprUnaryOp,
-    UnaryOp,
+    Expr, ExprAttribute, ExprBinOp, ExprBoolOp, ExprCompare, ExprUnaryOp, UnaryOp,
 };
 use ruff_python_trivia::CommentRanges;
 use ruff_python_trivia::{SimpleToken, SimpleTokenKind, SimpleTokenizer};
@@ -505,15 +504,7 @@ const fn is_simple_power_operand(expr: &Expr) -> bool {
         Expr::UnaryOp(ExprUnaryOp {
             op: UnaryOp::Not, ..
         }) => false,
-        Expr::Constant(ExprConstant {
-            value:
-                Constant::Complex { .. }
-                | Constant::Float(_)
-                | Constant::Int(_)
-                | Constant::None
-                | Constant::Bool(_),
-            ..
-        }) => true,
+        Expr::NumberLiteral(_) | Expr::NoneLiteral(_) | Expr::BooleanLiteral(_) => true,
         Expr::Name(_) => true,
         Expr::UnaryOp(ExprUnaryOp { operand, .. }) => is_simple_power_operand(operand),
         Expr::Attribute(ExprAttribute { value, .. }) => is_simple_power_operand(value),