Strenghten tests for missing_doc_code_examples lint

Author: GuillaumeGomez

Diff for: src/test/rustdoc-ui/lint-missing-doc-code-example.rs

@@ -38,3 +38,34 @@ pub mod module3 {
   //~^ ERROR
   pub fn test() {}
 }
+
+/// Doc, but no code example and it's fine!
+pub const Const: u32 = 0;
+/// Doc, but no code example and it's fine!
+pub static Static: u32 = 0;
+/// Doc, but no code example and it's fine!
+pub type Type = u32;
+
+/// Doc
+//~^ ERROR
+pub struct Struct {
+    /// Doc, but no code example and it's fine!
+    pub field: u32,
+}
+
+/// Doc
+//~^ ERROR
+pub enum Enum {
+    /// Doc, but no code example and it's fine!
+    X,
+}
+
+/// Doc
+//~^ ERROR
+#[repr(C)]
+union Union {
+    /// Doc, but no code example and it's fine!
+    a: i32,
+    /// Doc, but no code example and it's fine!
+    b: f32,
+}

Diff for: src/test/rustdoc-ui/lint-missing-doc-code-example.stderr

@@ -1,21 +1,39 @@
 error: missing code example in this documentation
-  --> $DIR/lint-missing-doc-code-example.rs:19:1
+  --> $DIR/lint-missing-doc-code-example.rs:49:1
    |
-LL | / mod module1 {
-LL | | }
-   | |_^
+LL | /// Doc
+   | ^^^^^^^
    |
 note: the lint level is defined here
   --> $DIR/lint-missing-doc-code-example.rs:2:9
    |
 LL | #![deny(missing_doc_code_examples)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^
 
+error: missing code example in this documentation
+  --> $DIR/lint-missing-doc-code-example.rs:63:1
+   |
+LL | /// Doc
+   | ^^^^^^^
+
+error: missing code example in this documentation
+  --> $DIR/lint-missing-doc-code-example.rs:56:1
+   |
+LL | /// Doc
+   | ^^^^^^^
+
+error: missing code example in this documentation
+  --> $DIR/lint-missing-doc-code-example.rs:19:1
+   |
+LL | / mod module1 {
+LL | | }
+   | |_^
+
 error: missing code example in this documentation
   --> $DIR/lint-missing-doc-code-example.rs:37:3
    |
 LL |   /// doc
    |   ^^^^^^^
 
-error: aborting due to 2 previous errors
+error: aborting due to 5 previous errors