Rollup merge of #132155 - GuillaumeGomez:impl-block-doc, r=rustdoc

Always display first line of impl blocks even when collapsed

Fixes https://github.com/rust-lang/rust/issues/130612.

It the line is too long, only the beginning will be visible:

![Screenshot from 2024-10-25 17-21-41](https://github.com/user-attachments/assets/dd2d912c-ad55-4410-8195-1d66a0a99ad4)

Otherwise, it looks like this:

![image](https://github.com/user-attachments/assets/1f40b9e0-2143-4b9d-a4b0-338a0cd740df)

Can be tested [here](https://rustdoc.crud.net/imperio/impl-block-doc/foo/struct.ImplDoc.html).

r? `@notriddle`

1 files changed, 39 insertions, 0 deletions

diff --git a/tests/rustdoc-gui/src/test_docs/lib.rs b/tests/rustdoc-gui/src/test_docs/lib.rs
index 352995c4903..91aa2c3fae5 100644
--- a/tests/rustdoc-gui/src/test_docs/lib.rs
+++ b/tests/rustdoc-gui/src/test_docs/lib.rs
@@ -652,3 +652,42 @@ pub mod long_list {
     //! * [`FromBytes`](#a) indicates that a type may safely be converted from an arbitrary byte
     //!   sequence
 }
+
+pub struct ImplDoc;
+
+/// bla sondfosdnf sdfasd fadsd fdsa f ads fad sf sad f sad fasdfsafsa df dsafasdasd fsa dfadsfasd
+/// fads fadfadd
+///
+/// bla
+impl ImplDoc {
+    pub fn bar() {}
+}
+
+/// bla
+///
+/// bla
+impl ImplDoc {
+    pub fn bar2() {}
+}
+
+// ignore-tidy-linelength
+/// | this::is::a::kinda::very::long::header::number::one | this::is::a::kinda::very::long::header::number::two | this::is::a::kinda::very::long::header::number::three |
+/// |-|-|-|
+/// | bla | bli | blob |
+impl ImplDoc {
+    pub fn bar3() {}
+}
+
+/// # h1
+///
+/// bla
+impl ImplDoc {
+    pub fn bar4() {}
+}
+
+/// * list
+/// * list
+/// * list
+impl ImplDoc {
+    pub fn bar5() {}
+}