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/expr_attribute.rs

@@ -1,6 +1,6 @@
 use ruff_formatter::{write, FormatRuleWithOptions};
 use ruff_python_ast::AnyNodeRef;
-use ruff_python_ast::{Constant, Expr, ExprAttribute, ExprConstant};
+use ruff_python_ast::{Expr, ExprAttribute, ExprNumberLiteral, Number};
 use ruff_python_trivia::{find_only_token_in_range, SimpleTokenKind};
 use ruff_text_size::{Ranged, TextRange};
 
@@ -167,17 +167,17 @@ impl NeedsParentheses for ExprAttribute {
 // Non Hex, octal or binary number literals need parentheses to disambiguate the attribute `.` from
 // a decimal point. Floating point numbers don't strictly need parentheses but it reads better (rather than 0.0.test()).
 fn is_base_ten_number_literal(expr: &Expr, source: &str) -> bool {
-    if let Some(ExprConstant { value, range }) = expr.as_constant_expr() {
+    if let Some(ExprNumberLiteral { value, range }) = expr.as_number_literal_expr() {
         match value {
-            Constant::Float(_) => true,
-            Constant::Int(_) => {
+            Number::Float(_) => true,
+            Number::Int(_) => {
                 let text = &source[*range];
                 !matches!(
                     text.as_bytes().get(0..2),
                     Some([b'0', b'x' | b'X' | b'o' | b'O' | b'b' | b'B'])
                 )
             }
-            _ => false,
+            Number::Complex { .. } => false,
         }
     } else {
         false