Add GUI test for long inline cfg labels display

tests/rustdoc-gui/label-next-to-symbol.goml

@@ -37,7 +37,6 @@ compare-elements-position: (
     ("y"),
 )
 
-
 // Mobile view
 set-window-size: (600, 600)
 // staggered layout with 2em spacing
@@ -64,3 +63,14 @@ compare-elements-position-false: (
     "//*[@class='desc docblock-short'][text()='a thing with a label']",
     ("y"),
 )
+
+// Ensure it doesn't expand.
+set-window-size: (800, 800)
+go-to: "file://" + |DOC_PATH| + "/test_docs/cfgs/index.html"
+// This part of the tags should not be on the same line as the beginning since the width
+// is too small for that.
+compare-elements-position-false: (
+    "//*[@class='stab portability']/code[text()='appservice-api-c']",
+    "//*[@class='stab portability']/code[text()='server']",
+    ("y"),
+)

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

@@ -507,3 +507,12 @@ pub enum Enum {
         },
     }
 }
+
+pub mod cfgs {
+    #[doc(cfg(all(
+        any(not(feature = "appservice-api-c"), not(feature = "appservice-api-s")),
+        any(not(feature = "client"), not(feature = "server")),
+    )))]
+    /// Some docs.
+    pub mod cfgs {}
+}