Add a divider between the element description and docs in hovers

Change-Id: I08dc275fd343dc7eaa0f0c6033b8889882889cd2
Reviewed-on: https://dart-review.googlesource.com/c/87406
Commit-Queue: Brian Wilkerson <[email protected]>
Reviewed-by: Brian Wilkerson <[email protected]>
Auto-Submit: Danny Tuppeny <[email protected]>

Author: DanTup

pkg/analysis_server/lib/src/lsp/handlers/handler_hover.dart

@@ -43,14 +43,15 @@ class HoverHandler extends MessageHandler<TextDocumentPositionParams, Hover> {
     }
 
     final content = new StringBuffer();
+    const divider = '---';
 
     // Description.
     if (hover.elementDescription != null) {
       content.writeln('```dart');
       if (hover.isDeprecated) {
         content.write('(deprecated) ');
       }
-      content..writeln(hover.elementDescription)..writeln('```')..writeln();
+      content..writeln(hover.elementDescription)..writeln('```');
     }
 
     // Source library.
@@ -66,6 +67,9 @@ class HoverHandler extends MessageHandler<TextDocumentPositionParams, Hover> {
 
     // Doc comments.
     if (hover.dartdoc != null) {
+      if (content.length != 0) {
+        content.writeln(divider);
+      }
       content.writeln(cleanDartdoc(hover.dartdoc));
     }
 

pkg/analysis_server/test/lsp/hover_test.dart

@@ -46,7 +46,7 @@ class HoverTest extends AbstractLspAnalysisServerTest {
 ```dart
 String abc
 ```
-
+---
 This is a string.
 
 With some [refs] and some