Fix I002 import insertion after docstring with multiple string statements (#19222)

Author: danparizher

crates/ruff_linter/resources/test/fixtures/isort/required_imports/multiple_strings.py

@@ -0,0 +1,5 @@
+"""This is a docstring."""
+"This is not a docstring."
+"This is also not a docstring."
+
+x = 1 

crates/ruff_linter/src/importer/insertion.rs

@@ -275,19 +275,12 @@ impl<'a> Insertion<'a> {
     }
 }
 
-/// Find the end of the last docstring.
+/// Find the end of the docstring (first string statement).
 fn match_docstring_end(body: &[Stmt]) -> Option<TextSize> {
-    let mut iter = body.iter();
-    let mut stmt = iter.next()?;
+    let stmt = body.first()?;
     if !is_docstring_stmt(stmt) {
         return None;
     }
-    for next in iter {
-        if !is_docstring_stmt(next) {
-            break;
-        }
-        stmt = next;
-    }
     Some(stmt.end())
 }
 
@@ -367,7 +360,7 @@ mod tests {
         .trim_start();
         assert_eq!(
             insert(contents)?,
-            Insertion::own_line("", TextSize::from(40), "\n")
+            Insertion::own_line("", TextSize::from(20), "\n")
         );
 
         let contents = r"

crates/ruff_linter/src/rules/isort/mod.rs

@@ -912,6 +912,7 @@ mod tests {
     #[test_case(Path::new("docstring.pyi"))]
     #[test_case(Path::new("docstring_only.py"))]
     #[test_case(Path::new("empty.py"))]
+    #[test_case(Path::new("multiple_strings.py"))]
     fn required_imports(path: &Path) -> Result<()> {
         let snapshot = format!("required_imports_{}", path.to_string_lossy());
         let diagnostics = test_path(

crates/ruff_linter/src/rules/isort/snapshots/ruff_linter__rules__isort__tests__required_imports_multiple_strings.py.snap

@@ -0,0 +1,18 @@
+---
+source: crates/ruff_linter/src/rules/isort/mod.rs
+---
+multiple_strings.py:1:1: I002 [*] Missing required import: `from __future__ import annotations`
+ℹ Safe fix
+1 1 | """This is a docstring."""
+  2 |+from __future__ import annotations
+2 3 | "This is not a docstring."
+3 4 | "This is also not a docstring."
+4 5 | 
+
+multiple_strings.py:1:1: I002 [*] Missing required import: `from __future__ import generator_stop`
+ℹ Safe fix
+1 1 | """This is a docstring."""
+  2 |+from __future__ import generator_stop
+2 3 | "This is not a docstring."
+3 4 | "This is also not a docstring."
+4 5 |