Assert that the separation of two annotations on function type during rendering it, is any whitespace-like symbol, not only whitespace itself

E.g. in quick doc mode (HTML), it may be line break

^KT-38747 Fixed

core/descriptors/src/org/jetbrains/kotlin/renderer/DescriptorRendererImpl.kt

@@ -323,7 +323,7 @@ internal class DescriptorRendererImpl(
                 insert(lengthBefore, '(')
             } else {
                 if (hasAnnotations) {
-                    assert(last() == ' ')
+                    assert(last().isWhitespace())
                     if (get(lastIndex - 1) != ')') {
                         // last annotation rendered without parenthesis - need to add them otherwise parsing will be incorrect
                         insert(lastIndex, "()")

idea/testData/editor/quickDoc/renderAnnotatedExtensionFunctionType.kt

@@ -0,0 +1,9 @@
+fun myFun<caret>(param: @MyAnnotation (String.() -> Unit)) {} // quick documentation myFun
+
+@Target(AnnotationTarget.TYPE)
+annotation class MyAnnotation
+
+//INFO: <div class='definition'><pre><font color="808080"><i>renderAnnotatedExtensionFunctionType.kt</i></font><br>public fun <b>myFun</b>(
+//INFO:     param: @<a href="psi_element://MyAnnotation">MyAnnotation</a>()
+//INFO: (String.() &rarr; Unit)
+//INFO: ): Unit</pre></div></pre></div><table class='sections'><p></table>

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

@@ -274,6 +274,11 @@ public class QuickDocProviderTestGenerated extends AbstractQuickDocProviderTest
         runTest("idea/testData/editor/quickDoc/OnMethodUsageWithTypeParameter.kt");
     }
 
+    @TestMetadata("renderAnnotatedExtensionFunctionType.kt")
+    public void testRenderAnnotatedExtensionFunctionType() throws Exception {
+        runTest("idea/testData/editor/quickDoc/renderAnnotatedExtensionFunctionType.kt");
+    }
+
     @TestMetadata("Samples.kt")
     public void testSamples() throws Exception {
         runTest("idea/testData/editor/quickDoc/Samples.kt");