Rollup merge of #112894 - GuillaumeGomez:gui-fields-display, r=notriddle

Fix union fields display

![Screenshot from 2023-06-21 16-47-24](https://github.com/rust-lang/rust/assets/3050060/833b0fe6-7fb6-4371-86c3-d82fa0c3fe49)

So two bugs in this screenshot: no whitespace between field name and type name, both fields are on the same line. Both problems come from issues in the templates because all whitespace are removed if a askama "command" follows.

r? `@notriddle`

tests/rustdoc-gui/fields.goml

@@ -0,0 +1,18 @@
+// This test checks that fields are displayed as expected (one by line).
+go-to: "file://" + |DOC_PATH| + "/test_docs/fields/struct.Struct.html"
+store-position: ("#structfield\.a", {"y": a_y})
+store-position: ("#structfield\.b", {"y": b_y})
+assert: |a_y| < |b_y|
+
+go-to: "file://" + |DOC_PATH| + "/test_docs/fields/union.Union.html"
+store-position: ("#structfield\.a", {"y": a_y})
+store-position: ("#structfield\.b", {"y": b_y})
+assert: |a_y| < |b_y|
+
+go-to: "file://" + |DOC_PATH| + "/test_docs/fields/enum.Enum.html"
+store-position: ("#variant\.A\.field\.a", {"y": a_y})
+store-position: ("#variant\.A\.field\.b", {"y": b_y})
+assert: |a_y| < |b_y|
+store-position: ("#variant\.B\.field\.a", {"y": a_y})
+store-position: ("#variant\.B\.field\.b", {"y": b_y})
+assert: |a_y| < |b_y|

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

@@ -486,3 +486,24 @@ pub mod search_results {
     }
 
 }
+
+pub mod fields {
+    pub struct Struct {
+        pub a: u8,
+        pub b: u32,
+    }
+    pub union Union {
+        pub a: u8,
+        pub b: u32,
+    }
+    pub enum Enum {
+        A {
+            a: u8,
+            b: u32,
+        },
+        B {
+            a: u8,
+            b: u32,
+        },
+    }
+}