Fix PLE251 rules with f-string escaping

**Summary** The `value` of the `FStringMiddle` for `f"""}}a�b"""` is `}a�b`, i.e. the curly brace escaping is decoded. If we iterate over string this gives us false indices causing exploding fixes for PLE251 rules (PLE2510, PLE2512, PLE2513, PLE2514, PLE2515). Instead, we now use the source range.

Handles #7455 (comment)
Handles #7455 (comment)

**Test Plan** Minimized fuzzing cases as fixtures.

crates/ruff_linter/src/rules/pylint/rules/invalid_string_characters.rs

@@ -180,7 +180,9 @@ pub(crate) fn invalid_string_characters(
 ) {
     let text = match tok {
         Tok::String { .. } => locator.slice(range),
-        Tok::FStringMiddle { value, .. } => value.as_str(),
+        // The string value has already decoded escaped curly braces, which would gives us wrong
+        // column information
+        Tok::FStringMiddle { .. } => &locator.contents()[range],
         _ => return,
     };
 

crates/ruff_linter/src/rules/pylint/snapshots/ruff_linter__rules__pylint__tests__PLE2510_invalid_characters.py.snap

@@ -48,6 +48,8 @@ invalid_characters.py:55:21: PLE2510 [*] Invalid unescaped character backspace,
 54 | 
 55 | nested_fstrings = f'{f'{f''}'}'
    |                      PLE2510
+56 | 
+57 | # https://github.com/astral-sh/ruff/issues/7455#issuecomment-1741998106
    |
    = help: Replace with escape sequence
 
@@ -57,5 +59,8 @@ invalid_characters.py:55:21: PLE2510 [*] Invalid unescaped character backspace,
 54 54 | 
 55    |-nested_fstrings = f'{f'{f''}'}'
    55 |+nested_fstrings = f'\b{f'{f''}'}'
+56 56 | 
+57 57 | # https://github.com/astral-sh/ruff/issues/7455#issuecomment-1741998106
+58 58 | x = f"""}}ab"""
 
 

crates/ruff_linter/src/rules/pylint/snapshots/ruff_linter__rules__pylint__tests__PLE2512_invalid_characters.py.snap

@@ -47,6 +47,8 @@ invalid_characters.py:55:25: PLE2512 [*] Invalid unescaped character SUB, use "\
 54 | 
 55 | nested_fstrings = f'{f'{f''}'}'
    |                         PLE2512
+56 | 
+57 | # https://github.com/astral-sh/ruff/issues/7455#issuecomment-1741998106
    |
    = help: Replace with escape sequence
 
@@ -56,5 +58,27 @@ invalid_characters.py:55:25: PLE2512 [*] Invalid unescaped character SUB, use "\
 54 54 | 
 55    |-nested_fstrings = f'{f'{f''}'}'
    55 |+nested_fstrings = f'{f'\x1A{f''}'}'
+56 56 | 
+57 57 | # https://github.com/astral-sh/ruff/issues/7455#issuecomment-1741998106
+58 58 | x = f"""}}ab"""
+
+invalid_characters.py:58:12: PLE2512 [*] Invalid unescaped character SUB, use "\x1A" instead
+   |
+57 | # https://github.com/astral-sh/ruff/issues/7455#issuecomment-1741998106
+58 | x = f"""}}ab"""
+   |             PLE2512
+59 | # https://github.com/astral-sh/ruff/issues/7455#issuecomment-1741998256
+60 | x = f"""}}ab"""
+   |
+   = help: Replace with escape sequence
+
+ℹ Fix
+55 55 | nested_fstrings = f'{f'{f''}'}'
+56 56 | 
+57 57 | # https://github.com/astral-sh/ruff/issues/7455#issuecomment-1741998106
+58    |-x = f"""}}ab"""
+   58 |+x = f"""}}a\x1Ab"""
+59 59 | # https://github.com/astral-sh/ruff/issues/7455#issuecomment-1741998256
+60 60 | x = f"""}}ab"""
 
 

crates/ruff_linter/src/rules/pylint/snapshots/ruff_linter__rules__pylint__tests__PLE2513_invalid_characters.py.snap

@@ -47,6 +47,8 @@ invalid_characters.py:55:29: PLE2513 [*] Invalid unescaped character ESC, use "\
 54 | 
 55 | nested_fstrings = f'{f'{f''}'}'
    |                            PLE2513
+56 | 
+57 | # https://github.com/astral-sh/ruff/issues/7455#issuecomment-1741998106
    |
    = help: Replace with escape sequence
 
@@ -56,5 +58,24 @@ invalid_characters.py:55:29: PLE2513 [*] Invalid unescaped character ESC, use "\
 54 54 | 
 55    |-nested_fstrings = f'{f'{f''}'}'
    55 |+nested_fstrings = f'{f'{f'\x1B'}'}'
+56 56 | 
+57 57 | # https://github.com/astral-sh/ruff/issues/7455#issuecomment-1741998106
+58 58 | x = f"""}}ab"""
+
+invalid_characters.py:60:12: PLE2513 [*] Invalid unescaped character ESC, use "\x1B" instead
+   |
+58 | x = f"""}}ab"""
+59 | # https://github.com/astral-sh/ruff/issues/7455#issuecomment-1741998256
+60 | x = f"""}}ab"""
+   |             PLE2513
+   |
+   = help: Replace with escape sequence
+
+ℹ Fix
+57 57 | # https://github.com/astral-sh/ruff/issues/7455#issuecomment-1741998106
+58 58 | x = f"""}}ab"""
+59 59 | # https://github.com/astral-sh/ruff/issues/7455#issuecomment-1741998256
+60    |-x = f"""}}ab"""
+   60 |+x = f"""}}a\x1Bb"""
 
 

crates/ruff_linter/src/rules/pylint/snapshots/ruff_linter__rules__pylint__tests__PLE2515_invalid_characters.py.snap

@@ -141,6 +141,7 @@ invalid_characters.py:53:61: PLE2515 [*] Invalid unescaped character zero-width-
    53 |+zwsp_after_multicharacter_grapheme_cluster = f"ಫ್ರಾನ್ಸಿಸ್ಕೊ \u200b​"
 54 54 | 
 55 55 | nested_fstrings = f'{f'{f''}'}'
+56 56 | 
 
 invalid_characters.py:53:62: PLE2515 [*] Invalid unescaped character zero-width-space, use "\u200B" instead
    |
@@ -161,5 +162,6 @@ invalid_characters.py:53:62: PLE2515 [*] Invalid unescaped character zero-width-
    53 |+zwsp_after_multicharacter_grapheme_cluster = f"ಫ್ರಾನ್ಸಿಸ್ಕೊ ​\u200b"
 54 54 | 
 55 55 | nested_fstrings = f'{f'{f''}'}'
+56 56 |