Rollup merge of #89632 - GuillaumeGomez:fix-docblock-code, r=jsha

Fix docblock code display on mobile

Fixes #89618.

Before:

![Screenshot from 2021-10-07 12-01-37](https://user-images.githubusercontent.com/3050060/136363624-72bedddd-b45e-48a0-89b4-6563612f8677.png)

After:

![Screenshot from 2021-10-07 20-17-21](https://user-images.githubusercontent.com/3050060/136440704-fa9ffa68-8e94-46a7-b556-c41aa5153750.png)

r? `@jsha`

src/librustdoc/html/static/css/rustdoc.css

@@ -1969,4 +1969,8 @@ details.undocumented[open] > summary::before {
 	.docblock {
 		margin-left: 12px;
 	}
+
+	.docblock code {
+		overflow-wrap: anywhere;
+	}
 }

src/test/rustdoc-gui/docblock-big-code-mobile.goml

@@ -0,0 +1,9 @@
+// If we have a long `<code>`, we need to ensure that it'll be fully displayed on mobile, meaning
+// that it'll be on two lines.
+emulate: "iPhone 8" // it has the following size: (375, 667)
+goto: file://|DOC_PATH|/test_docs/long_code_block/index.html
+// We now check that the block is on two lines:
+show-text: true // We need to enable text draw to be able to have the "real" size
+// Little explanations for this test: if the text wasn't displayed on two lines, it would take
+// around 20px (which is the font size).
+assert-property: (".docblock p > code", {"offsetHeight": "42"})

src/test/rustdoc-gui/src/test_docs/lib.rs

@@ -120,3 +120,6 @@ pub type SomeType = u32;
 pub mod huge_amount_of_consts {
     include!(concat!(env!("OUT_DIR"), "/huge_amount_of_consts.rs"));
 }
+
+/// Very long code text `hereIgoWithLongTextBecauseWhyNotAndWhyWouldntI`.
+pub mod long_code_block {}