don't trim whitespace when converting whitespace to HTML

#KT-10998 Fixed

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

@@ -121,6 +121,10 @@ object KDocRenderer {
     }
 
     fun MarkdownNode.toHtml(): String {
+        if (node.type == MarkdownTokenTypes.WHITE_SPACE) {
+            return text   // do not trim trailing whitespace
+        }
+
         val sb = StringBuilder()
         visit { node, processChildren ->
             fun wrapChildren(tag: String, newline: Boolean = false) {

idea/testData/editor/quickDoc/OnMethodUsageWithMarkdown.kt

@@ -23,7 +23,7 @@ fun test() {
 }
 
 //INFO: <b>public</b> <b>fun</b> testMethod(): Unit <i>defined in</i> root package<p>Some documentation. <strong>Bold</strong> <em>underline</em> <code>code</code> foo: bar (baz) <a href="psi_element://quux">quux</a>  'apos'</p>
-//INFO: <p><a href="http://www.kotlinlang.org">Kotlin</a> <a href="http://www.ibm.com">a<strong>b</strong><strong>d</strong>kas</a></p>
+//INFO: <p><a href="http://www.kotlinlang.org">Kotlin</a> <a href="http://www.ibm.com">a<strong>b</strong><strong>d</strong> kas</a></p>
 //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><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>

idea/testData/editor/quickDoc/OnMethodUsageWithReturnAndLink.kt

@@ -0,0 +1,18 @@
+/**
+Some documentation
+
+ * @param a Some int
+ * @param b String
+ * @return Return [a] and nothing else
+ */
+fun testMethod(a: Int, b: String) {
+
+}
+
+fun test() {
+    <caret>testMethod(1, "value")
+}
+
+//INFO: <b>public</b> <b>fun</b> testMethod(a: Int, b: String): Unit <i>defined in</i> root package<p>Some documentation</p>
+//INFO: <dl><dt><b>Parameters:</b></dt><dd><code>a</code> - Some int</dd><dd><code>b</code> - String</dd></dl>
+//INFO: <dl><dt><b>Returns:</b></dt><dd>Return <a href="psi_element://a">a</a> and nothing else</dd></dl>

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

@@ -143,6 +143,12 @@ public class QuickDocProviderTestGenerated extends AbstractQuickDocProviderTest
         doTest(fileName);
     }
 
+    @TestMetadata("OnMethodUsageWithReturnAndLink.kt")
+    public void testOnMethodUsageWithReturnAndLink() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/testData/editor/quickDoc/OnMethodUsageWithReturnAndLink.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("OnMethodUsageWithReturnAndThrows.kt")
     public void testOnMethodUsageWithReturnAndThrows() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("idea/testData/editor/quickDoc/OnMethodUsageWithReturnAndThrows.kt");