fix up links to relative stylesheets

libraries/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/templates/ClassExtensionsTemplate.kt

@@ -15,6 +15,8 @@ import org.jetbrains.kotlin.doc.model.KProperty
 class ClassExtensionsTemplate(m: KModel, p: KPackage, k: KClass,
         val functions: Collection<KFunction>, val properties: Collection<KProperty>) : ClassTemplate(m, p, k) {
 
+    protected override fun relativePrefix(): String = "${pkg.nameAsRelativePath}${klass.pkg.nameAsRelativePath}"
+
     override fun pageTitle(): String = "${klass.name} Extensions fom ${pkg.name} (${model.title})"
 
     override fun printBody(): Unit {

libraries/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/templates/ClassTemplate.kt

@@ -28,7 +28,7 @@ ${pageTitle()}
 
 <META NAME="date" CONTENT="2012-01-09">
 <META NAME="date" CONTENT="2012-01-09">
-<LINK REL="stylesheet" TYPE="text/css" HREF="${pkg.nameAsRelativePath}stylesheet.css" TITLE="Style">
+<LINK REL="stylesheet" TYPE="text/css" HREF="${relativePrefix()}stylesheet.css" TITLE="Style">
 
 <SCRIPT type="text/javascript">
 function windowTitle()