Add test for codeblocks overflow

Author: GuillaumeGomez

src/test/rustdoc-gui/code-blocks-overflow.goml

@@ -0,0 +1,8 @@
+// This test ensures that codeblocks content don't overflow.
+goto: file://|DOC_PATH|/lib2/sub_mod/struct.Foo.html
+size: (1080, 600)
+// There should be two codeblocks: a rust one and a non-rust one.
+assert-count: (".docblock > .example-wrap", 2)
+assert: ".docblock > .example-wrap > .language-txt"
+assert: ".docblock > .example-wrap > .rust-example-rendered"
+assert-css: (".docblock > .example-wrap > pre", {"width": "796px", "overflow-x": "auto"}, ALL)

src/test/rustdoc-gui/src/lib2/lib.rs

@@ -1,3 +1,5 @@
+// ignore-tidy-linelength
+
 pub mod module {
     pub mod sub_module {
         pub mod sub_sub_module {
@@ -32,4 +34,16 @@ impl Trait for Foo {
     const Y: u32 = 0;
 }
 
+
 impl implementors::Whatever for Foo {}
+
+pub mod sub_mod {
+    /// ```txt
+    /// aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+    /// ```
+    ///
+    /// ```
+    /// aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+    /// ```
+    pub struct Foo;
+}