don't lose ! when rendering markdown

#KT-13000 Fixed

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

@@ -193,6 +193,7 @@ object KDocRenderer {
                 MarkdownTokenTypes.RPAREN,
                 MarkdownTokenTypes.LBRACKET,
                 MarkdownTokenTypes.RBRACKET,
+                MarkdownTokenTypes.EXCLAMATION_MARK,
                 MarkdownTokenTypes.CODE_FENCE_CONTENT-> {
                     sb.append(nodeText)
                 }

idea/testData/editor/quickDoc/OnMethodUsageWithMarkdown.kt

@@ -10,6 +10,8 @@
  *
  * This is _emphasized text_ but text_with_underscores has to preserve the underscores.
  * Single stars embedded in a word like Embedded*Star have to be preserved as well.
+ *
+ * Exclamation marks are also important! Also in `code blocks!`
  */
 fun testMethod() {
 
@@ -27,3 +29,4 @@ fun test() {
 //INFO: <p><a href="psi_element://C">C</a></p>
 //INFO: <p><a href="psi_element://C">See <strong>this</strong> class</a></p>
 //INFO: <p>This is <em>emphasized text</em> but text_with_underscores has to preserve the underscores. Single stars embedded in a word like Embedded*Star have to be preserved as well.</p>
+//INFO: <p>Exclamation marks are also important! Also in <code>code blocks!</code></p>