Fix PLE251 rules with f-string escaping (#7741)

**Summary** The `value` of the `FStringMiddle` for `f"""}}ab"""` is
`}ab`, 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
https://github.com/astral-sh/ruff/issues/7455#issuecomment-1741998106
Handles
https://github.com/astral-sh/ruff/issues/7455#issuecomment-1741998256

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

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

@@ -179,8 +179,9 @@ pub(crate) fn invalid_string_characters(
     locator: &Locator,
 ) {
     let text = match tok {
-        Tok::String { .. } => locator.slice(range),
+        // We can't use the `value` field since it's decoded and e.g. for f-strings removed a curly
-        Tok::FStringMiddle { value, .. } => value.as_str(),
+        // brace that escaped another curly brace, which would gives us wrong column information.
+        Tok::String { .. } | Tok::FStringMiddle { .. } => locator.slice(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 |