[red-knot] Infer subscript expression types for bytes literals (#13901)

## Summary

Infer subscript expression types for bytes literals:
```py
b = b"\x00abc\xff"

reveal_type(b[0])  # revealed: Literal[b"\x00"]
reveal_type(b[1])  # revealed: Literal[b"a"]
reveal_type(b[-1])  # revealed: Literal[b"\xff"]
reveal_type(b[-2])  # revealed: Literal[b"c"]

reveal_type(b[False])  # revealed: Literal[b"\x00"]
reveal_type(b[True])  # revealed: Literal[b"a"]
```


part of #13689
(https://github.com/astral-sh/ruff/issues/13689#issuecomment-2404285064)

## Test Plan

- New Markdown-based tests (see `mdtest/subscript/bytes.md`)
- Added missing test for `string_literal[bool_literal]`

crates/red_knot_python_semantic/resources/mdtest/subscript/string.md

@@ -10,6 +10,9 @@ reveal_type(s[1])  # revealed: Literal["b"]
 reveal_type(s[-1])  # revealed: Literal["e"]
 reveal_type(s[-2])  # revealed: Literal["d"]
 
+reveal_type(s[False])  # revealed: Literal["a"]
+reveal_type(s[True])  # revealed: Literal["b"]
+
 a = s[8]  # error: [index-out-of-bounds] "Index 8 is out of bounds for string `Literal["abcde"]` with length 5"
 reveal_type(a)  # revealed: Unknown
 
@@ -20,11 +23,10 @@ reveal_type(b)  # revealed: Unknown
 ## Function return
 
 ```py
-def add(x: int, y: int) -> int:
-    return x + y
+def int_instance() -> int: ...
 
 
-a = "abcde"[add(0, 1)]
+a = "abcde"[int_instance()]
 # TODO: Support overloads... Should be `str`
 reveal_type(a)  # revealed: @Todo
 ```