Fix panic in D208 with multibyte indent (#9147)

Fix #9080

Example, where `[]` is a 2 byte non-breaking space:
```
def f():
    """ Docstring header
^^^^ Real indentation is 4 chars
      docstring body, over-indented
^^^^^^ Over-indentation is 6 - 4 = 2 chars due to this line
   [] []  docstring body 2, further indented
^^^^^ We take these 4 chars/5 bytes to match the docstring ...
     ^^^ ... and these 2 chars/3 bytes to remove the `over_indented_size` ...
        ^^ ... but preserve this real indent
```

crates/ruff_linter/resources/test/fixtures/pydocstyle/D.py

@@ -715,3 +715,10 @@ def retain_extra_whitespace_not_overindented():
         This is overindented, but since one line is not overindented this should not raise
             And so is this, but it we should preserve the extra space on this line relative
     """
+
+
+def inconsistent_indent_byte_size():
+    """There's a non-breaking space (2-bytes) after 3 spaces (https://github.com/astral-sh/ruff/issues/9080).
+
+       Returns:
+    """

crates/ruff_linter/src/rules/pydocstyle/rules/indent.rs

@@ -254,14 +254,26 @@ pub(crate) fn indent(checker: &mut Checker, docstring: &Docstring) {
                     Edit::range_deletion(TextRange::at(line.start(), line_indent.text_len()))
                 } else {
                     // Convert the character count to an offset within the source.
+                    // Example, where `[]` is a 2 byte non-breaking space:
+                    // ```
+                    // def f():
+                    //     """ Docstring header
+                    // ^^^^ Real indentation is 4 chars
+                    //       docstring body, over-indented
+                    // ^^^^^^ Over-indentation is 6 - 4 = 2 chars due to this line
+                    //    [] []  docstring body 2, further indented
+                    // ^^^^^ We take these 4 chars/5 bytes to match the docstring ...
+                    //      ^^^ ... and these 2 chars/3 bytes to remove the `over_indented_size` ...
+                    //         ^^ ... but preserve this real indent
+                    // ```
                     let offset = checker
                         .locator()
-                        .after(line.start() + indent.text_len())
+                        .after(line.start())
                         .chars()
-                        .take(over_indented_size)
+                        .take(docstring.indentation.chars().count() + over_indented_size)
                         .map(TextLen::text_len)
                         .sum::<TextSize>();
-                    let range = TextRange::at(line.start(), indent.text_len() + offset);
+                    let range = TextRange::at(line.start(), offset);
                     Edit::range_replacement(indent, range)
                 };
                 diagnostic.set_fix(Fix::safe_edit(edit));

crates/ruff_linter/src/rules/pydocstyle/snapshots/ruff_linter__rules__pydocstyle__tests__D208_D.py.snap

@@ -411,4 +411,22 @@ D.py:707:1: D208 [*] Docstring is over-indented
 709 709 | 
 710 710 | 
 
+D.py:723:1: D208 [*] Docstring is over-indented
+    |
+721 |     """There's a non-breaking space (2-bytes) after 3 spaces (https://github.com/astral-sh/ruff/issues/9080).
+722 | 
+723 |        Returns:
+    |  D208
+724 |     """
+    |
+    = help: Remove over-indentation
+
+ℹ Safe fix
+720 720 | def inconsistent_indent_byte_size():
+721 721 |     """There's a non-breaking space (2-bytes) after 3 spaces (https://github.com/astral-sh/ruff/issues/9080).
+722 722 | 
+723     |-       Returns:
+    723 |+    Returns:
+724 724 |     """
+
 

crates/ruff_linter/src/rules/pydocstyle/snapshots/ruff_linter__rules__pydocstyle__tests__D213_D.py.snap

@@ -679,4 +679,27 @@ D.py:712:5: D213 [*] Multi-line docstring summary should start at the second lin
 714 715 |     This is not overindented
 715 716 |         This is overindented, but since one line is not overindented this should not raise
 
+D.py:721:5: D213 [*] Multi-line docstring summary should start at the second line
+    |
+720 |   def inconsistent_indent_byte_size():
+721 |       """There's a non-breaking space (2-bytes) after 3 spaces (https://github.com/astral-sh/ruff/issues/9080).
+    |  _____^
+722 | | 
+723 | |        Returns:
+724 | |     """
+    | |_______^ D213
+    |
+    = help: Insert line break and indentation after opening quotes
+
+ℹ Safe fix
+718 718 | 
+719 719 | 
+720 720 | def inconsistent_indent_byte_size():
+721     |-    """There's a non-breaking space (2-bytes) after 3 spaces (https://github.com/astral-sh/ruff/issues/9080).
+    721 |+    """
+    722 |+    There's a non-breaking space (2-bytes) after 3 spaces (https://github.com/astral-sh/ruff/issues/9080).
+722 723 | 
+723 724 |        Returns:
+724 725 |     """
+