Properly format @example in quick info (#2329)

Author: ahejlsberg

internal/ls/hover.go

@@ -12,6 +12,7 @@ import (
 	"github.com/microsoft/typescript-go/internal/collections"
 	"github.com/microsoft/typescript-go/internal/core"
 	"github.com/microsoft/typescript-go/internal/lsp/lsproto"
+	"github.com/microsoft/typescript-go/internal/scanner"
 )
 
 const (
@@ -109,14 +110,19 @@ func (l *LanguageService) getDocumentationFromDeclaration(c *checker.Checker, de
 						}
 					}
 					comments := tag.Comments()
-					if len(comments) != 0 {
-						if commentHasPrefix(comments, "```") {
+					if tag.Kind == ast.KindJSDocTag && tag.TagName().Text() == "example" {
+						b.WriteString("\n")
+						commentText := strings.TrimRight(getCommentText(comments), " \t\r\n")
+						if len(commentText) > 6 && strings.HasPrefix(commentText, "```") && strings.HasSuffix(commentText, "```") && strings.Contains(commentText, "\n") {
+							b.WriteString(commentText)
 							b.WriteString("\n")
 						} else {
-							b.WriteString(" ")
-							if !commentHasPrefix(comments, "-") {
-								b.WriteString("— ")
-							}
+							writeCode(&b, "tsx", commentText)
+						}
+					} else if len(comments) != 0 {
+						b.WriteString(" ")
+						if !commentHasPrefix(comments, "-") {
+							b.WriteString("— ")
 						}
 						l.writeComments(&b, c, comments, isMarkdown)
 					}
@@ -127,6 +133,19 @@ func (l *LanguageService) getDocumentationFromDeclaration(c *checker.Checker, de
 	return b.String()
 }
 
+func getCommentText(comments []*ast.Node) string {
+	var b strings.Builder
+	for _, comment := range comments {
+		switch comment.Kind {
+		case ast.KindJSDocText:
+			b.WriteString(comment.Text())
+		case ast.KindJSDocLink, ast.KindJSDocLinkCode, ast.KindJSDocLinkPlain:
+			b.WriteString(scanner.GetTextOfNode(comment))
+		}
+	}
+	return b.String()
+}
+
 func formatQuickInfo(quickInfo string) string {
 	var b strings.Builder
 	b.Grow(32)

testdata/baselines/reference/fourslash/quickInfo/quickInfoForJSDocCodefence.baseline

@@ -36,9 +36,12 @@
 // | ```
 // | 
 // | 
-// | *@example* — ``
+// | *@example*
+// | ```tsx
+// | ``
 // | 1 + 2
 // | `
+// | ```
 // | 
 // | ----------------------------------------------------------------------
 //     return '2';
@@ -84,7 +87,7 @@
     "item": {
       "contents": {
         "kind": "markdown",
-        "value": "```tsx\nfunction boo(): string\n```\n\n\n*@example* — ``\n1 + 2\n`\n"
+        "value": "```tsx\nfunction boo(): string\n```\n\n\n*@example*\n```tsx\n``\n1 + 2\n`\n```\n"
       },
       "range": {
         "start": {

testdata/baselines/reference/fourslash/quickInfo/quickInfoForJSDocUnknownTag.baseline

@@ -14,9 +14,12 @@
 // | ```
 // | 
 // | 
-// | *@example* — if (true) {
+// | *@example*
+// | ```tsx
+// | if (true) {
 // |     foo()
 // | }
+// | ```
 // | 
 // | ----------------------------------------------------------------------
 //     return '2';
@@ -35,9 +38,12 @@
 // | ```
 // | 
 // | 
-// | *@example* — {
+// | *@example*
+// | ```tsx
+// | {
 // |     foo()
 // | }
+// | ```
 // | 
 // | ----------------------------------------------------------------------
 //     return '2';
@@ -56,9 +62,12 @@
 // | ```
 // | 
 // | 
-// | *@example* —   x y
+// | *@example*
+// | ```tsx
+// |   x y
 // |   12345
 // |      b
+// | ```
 // | 
 // | ----------------------------------------------------------------------
 //     return '2';
@@ -80,9 +89,12 @@
 // | 
 // | *@func*
 // | 
-// | *@example* —   x y
+// | *@example*
+// | ```tsx
+// |   x y
 // |   12345
 // |      b
+// | ```
 // | 
 // | ----------------------------------------------------------------------
 //     return '2';
@@ -103,9 +115,12 @@
 // | 
 // | *@func*
 // | 
-// | *@example* — x y
+// | *@example*
+// | ```tsx
+// | x y
 // | 12345
 // |    b
+// | ```
 // | 
 // | ----------------------------------------------------------------------
 //     return '2';
@@ -124,7 +139,7 @@
     "item": {
       "contents": {
         "kind": "markdown",
-        "value": "```tsx\nfunction foo(): string\n```\n\n\n*@example* — if (true) {\n    foo()\n}\n"
+        "value": "```tsx\nfunction foo(): string\n```\n\n\n*@example*\n```tsx\nif (true) {\n    foo()\n}\n```\n"
       },
       "range": {
         "start": {
@@ -151,7 +166,7 @@
     "item": {
       "contents": {
         "kind": "markdown",
-        "value": "```tsx\nfunction foo2(): string\n```\n\n\n*@example* — {\n    foo()\n}\n"
+        "value": "```tsx\nfunction foo2(): string\n```\n\n\n*@example*\n```tsx\n{\n    foo()\n}\n```\n"
       },
       "range": {
         "start": {
@@ -178,7 +193,7 @@
     "item": {
       "contents": {
         "kind": "markdown",
-        "value": "```tsx\nfunction moo(): string\n```\n\n\n*@example* —   x y\n  12345\n     b\n"
+        "value": "```tsx\nfunction moo(): string\n```\n\n\n*@example*\n```tsx\n  x y\n  12345\n     b\n```\n"
       },
       "range": {
         "start": {
@@ -205,7 +220,7 @@
     "item": {
       "contents": {
         "kind": "markdown",
-        "value": "```tsx\nfunction boo(): string\n```\n\n\n*@func*\n\n*@example* —   x y\n  12345\n     b\n"
+        "value": "```tsx\nfunction boo(): string\n```\n\n\n*@func*\n\n*@example*\n```tsx\n  x y\n  12345\n     b\n```\n"
       },
       "range": {
         "start": {
@@ -232,7 +247,7 @@
     "item": {
       "contents": {
         "kind": "markdown",
-        "value": "```tsx\nfunction goo(): string\n```\n\n\n*@func*\n\n*@example* — x y\n12345\n   b\n"
+        "value": "```tsx\nfunction goo(): string\n```\n\n\n*@func*\n\n*@example*\n```tsx\nx y\n12345\n   b\n```\n"
       },
       "range": {
         "start": {