Quick doc: show default parameter value

#KT-19069 Fixed

idea/src/org/jetbrains/kotlin/idea/KotlinDocumentationProvider.kt

@@ -58,6 +58,7 @@ import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameSafe
 import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameUnsafe
 import org.jetbrains.kotlin.resolve.descriptorUtil.getSuperClassNotAny
 import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
+import org.jetbrains.kotlin.resolve.source.getPsi
 import org.jetbrains.kotlin.utils.addToStdlib.constant
 import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 
@@ -178,6 +179,7 @@ open class KotlinDocumentationProviderCompatBase : AbstractDocumentationProvider
             eachAnnotationOnNewLine = true
             boldOnlyForNamesInHtml = true
             excludedTypeAnnotationClasses = NULLABILITY_ANNOTATIONS
+            defaultParameterValueRenderer = { (it.source.getPsi() as? KtParameter)?.defaultValue?.text ?: "..." }
         }
 
         fun StringBuilder.renderKDoc(contentTag: KDocTag, sections: List<KDocSection>) {

idea/testData/editor/quickDoc/OnMethodUsage.kt

@@ -4,7 +4,7 @@ Some documentation
  * @param a Some int
  * @param b String
  */
-fun testMethod(a: Int, b: String) {
+fun testMethod(a: Int, b: String = "default") {
 
 }
 
@@ -14,5 +14,5 @@ fun test() {
 
 //INFO: <div class='definition'><pre><font color="808080"><i>OnMethodUsage.kt</i></font><br>public fun <b>testMethod</b>(
 //INFO:     a: Int,
-//INFO:     b: String
+//INFO:     b: String = "default"
 //INFO: ): Unit</pre></div><div class='content'><p>Some documentation</p></div><table class='sections'><tr><td valign='top' class='section'><p>Params:</td><td valign='top'><p><code>a</code> - Some int<p><code>b</code> - String</td></table>