Merge #4559

4559: Module name on hover shows another newline after it r=matklad a=Arthamys

This changes the display of hover information to add a newline between the module path of the item and the signature of the item, as suggested in #3813 

**Before**

![before_3813](https://user-images.githubusercontent.com/11710698/82609224-5d517d80-9bbc-11ea-9a08-0a1558409c6b.png)

**After**

![after_3813](https://user-images.githubusercontent.com/11710698/82609208-562a6f80-9bbc-11ea-8cb6-4430269c5800.png)

Co-authored-by: Galilée 'Bill' Enguehard <galilee.enguehard@gmail.com>

crates/ra_ide/src/display.rs

@@ -79,14 +79,14 @@ pub(crate) fn rust_code_markup_with_doc(
     doc: Option<&str>,
     mod_path: Option<&str>,
 ) -> String {
-    let mut buf = "```rust\n".to_owned();
+    let mut buf = String::new();
 
     if let Some(mod_path) = mod_path {
         if !mod_path.is_empty() {
-            format_to!(buf, "{}\n", mod_path);
+            format_to!(buf, "{}\n___\n\n", mod_path);
         }
     }
-    format_to!(buf, "{}\n```", code);
+    format_to!(buf, "```rust\n{}\n```", code);
 
     if let Some(doc) = doc {
         format_to!(buf, "\n\n{}", doc);

crates/ra_ide/src/hover.rs

@@ -405,7 +405,7 @@ mod tests {
                 };
             }
         "#,
-            &["Foo\nfield_a: u32"],
+            &["Foo\n___\n\n```rust\nfield_a: u32"],
         );
 
         // Hovering over the field in the definition
@@ -422,7 +422,7 @@ mod tests {
                 };
             }
         "#,
-            &["Foo\nfield_a: u32"],
+            &["Foo\n___\n\n```rust\nfield_a: u32"],
         );
     }
 
@@ -475,7 +475,7 @@ fn main() {
             ",
         );
         let hover = analysis.hover(position).unwrap().unwrap();
-        assert_eq!(trim_markup_opt(hover.info.first()), Some("Option\nSome"));
+        assert_eq!(trim_markup_opt(hover.info.first()), Some("Option\n___\n\n```rust\nSome"));
 
         let (analysis, position) = single_file_with_position(
             "
@@ -503,6 +503,9 @@ fn main() {
         "#,
             &["
 Option
+___
+
+```rust
 None
 ```
 
@@ -524,6 +527,9 @@ The None variant
         "#,
             &["
 Option
+___
+
+```rust
 Some
 ```
 
@@ -606,7 +612,10 @@ fn func(foo: i32) { if true { <|>foo; }; }
             ",
         );
         let hover = analysis.hover(position).unwrap().unwrap();
-        assert_eq!(trim_markup_opt(hover.info.first()), Some("wrapper::Thing\nfn new() -> Thing"));
+        assert_eq!(
+            trim_markup_opt(hover.info.first()),
+            Some("wrapper::Thing\n___\n\n```rust\nfn new() -> Thing")
+        );
     }
 
     #[test]

crates/rust-analyzer/tests/heavy_tests/main.rs

@@ -774,5 +774,5 @@ pub fn foo(_input: TokenStream) -> TokenStream {
     });
 
     let value = res.get("contents").unwrap().get("value").unwrap().to_string();
-    assert_eq!(value, r#""```rust\nfoo::Bar\nfn bar()\n```""#)
+    assert_eq!(value, r#""foo::Bar\n___\n\n```rust\nfn bar()\n```""#)
 }