Fix for KT-13038 Quick doc should escape HTML entities in code blocks

idea/src/org/jetbrains/kotlin/idea/kdoc/KDocRenderer.kt

@@ -203,10 +203,12 @@ object KDocRenderer {
                 MarkdownTokenTypes.RPAREN,
                 MarkdownTokenTypes.LBRACKET,
                 MarkdownTokenTypes.RBRACKET,
-                MarkdownTokenTypes.EXCLAMATION_MARK,
+                MarkdownTokenTypes.EXCLAMATION_MARK -> {
-                MarkdownTokenTypes.CODE_FENCE_CONTENT-> {
                     sb.append(nodeText)
                 }
+                MarkdownTokenTypes.CODE_FENCE_CONTENT -> {
+                    sb.append(nodeText.htmlEscape())
+                }
                 MarkdownTokenTypes.EOL -> {
                     val parentType = node.parent?.type
                     if (parentType == MarkdownElementTypes.CODE_BLOCK || parentType == MarkdownElementTypes.CODE_FENCE) {

idea/testData/editor/quickDoc/EscapeHtmlInsideCodeBlocks.kt

@@ -0,0 +1,14 @@
+/**
+ * Code block:
+ * ``` kotlin
+ * A<T>
+ * ```
+ * Code span:
+ * `<T>` is type parameter
+ */
+class <caret>A<T>
+
+//INFO: <b>public</b> <b>final</b> <b>class</b> A&lt;T&gt; <i>defined in</i> root package<p>Code block:</p>
+//INFO: <pre><code>
+//INFO: A&lt;T&gt;
+//INFO: </code></pre><p>Code span: <code>&lt;T&gt;</code> is type parameter</p>

idea/tests/org/jetbrains/kotlin/idea/editor/quickDoc/QuickDocProviderTestGenerated.java

@@ -72,6 +72,12 @@ public class QuickDocProviderTestGenerated extends AbstractQuickDocProviderTest
         doTest(fileName);
     }
 
+    @TestMetadata("EscapeHtmlInsideCodeBlocks.kt")
+    public void testEscapeHtmlInsideCodeBlocks() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/testData/editor/quickDoc/EscapeHtmlInsideCodeBlocks.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("JavaClassUsedInKotlin.kt")
     public void testJavaClassUsedInKotlin() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("idea/testData/editor/quickDoc/JavaClassUsedInKotlin.kt");