Minor: Add @NotNull annotation

annotations/com/intellij/refactoring/annotations.xml

@@ -8,7 +8,10 @@
   <item name='com.intellij.refactoring.BaseRefactoringProcessor myProject'>
     <annotation name='org.jetbrains.annotations.NotNull'/>
   </item>
-  <item
+    <item name='com.intellij.refactoring.BaseRefactoringProcessor void performRefactoring(com.intellij.usageView.UsageInfo[]) 0'>
+        <annotation name='org.jetbrains.annotations.NotNull'/>
+    </item>
+    <item
       name='com.intellij.refactoring.BaseRefactoringProcessor.ConflictsInTestsException java.util.Collection&lt;java.lang.String&gt; getMessages()'>
     <annotation name='org.jetbrains.annotations.NotNull'/>
   </item>

idea/src/org/jetbrains/jet/plugin/intentions/ReplaceExplicitFunctionLiteralParamWithItIntention.kt

@@ -98,7 +98,7 @@ public class ReplaceExplicitFunctionLiteralParamWithItIntention() : PsiElementBa
                                                                        false,
                                                                        false
     ) {
-        public override fun performRefactoring(usages: Array<out UsageInfo>?) {
+        public override fun performRefactoring(usages: Array<out UsageInfo>) {
             super.performRefactoring(usages)
             funcLiteral.deleteChildRange(funcLiteral.getValueParameterList(), funcLiteral.getArrowNode()!!.getPsi())
             if (cursorWasOverParameterList) {

idea/src/org/jetbrains/jet/plugin/refactoring/move/moveTopLevelDeclarations/MoveKotlinTopLevelDeclarationsProcessor.kt

@@ -219,7 +219,7 @@ public class MoveKotlinTopLevelDeclarationsProcessor(project: Project, val optio
         return showConflicts(conflicts, refUsages.get())
     }
 
-    override fun performRefactoring(usages: Array<out UsageInfo>?) {
+    override fun performRefactoring(usages: Array<out UsageInfo>) {
         fun moveDeclaration(
                 declaration: JetNamedDeclaration,
                 moveTarget: KotlinMoveTarget,