[FIR] Fix nullability rendering for class like types in html dump

compiler/fir/dump/src/org/jetbrains/kotlin/fir/dump/HtmlFirDump.kt

@@ -703,6 +703,9 @@ class HtmlFirDump internal constructor(private var linkResolver: FirLinkResolver
                         simpleName(type.lookupTag.name)
                     }
                     generateTypeArguments(type)
+                    if (type.isMarkedNullable) {
+                        +"?"
+                    }
                     +" = "
                     val directlyExpanded = type.directExpansionType(session)
                     if (directlyExpanded != null) {
@@ -716,6 +719,9 @@ class HtmlFirDump internal constructor(private var linkResolver: FirLinkResolver
                         fqn(type.lookupTag.classId.relativeClassName)
                     }
                     generateTypeArguments(type)
+                    if (type.isMarkedNullable) {
+                        +"?"
+                    }
                 }
             }
         }