Fix minor issues in layout

Author: pavel-alay

layout/src/main/java/com/itextpdf/layout/IPropertyContainer.java

@@ -49,7 +49,6 @@ This file is part of the iText (R) project.
 /**
  * A generic Map-like interface that defines methods for storing and retrieving
  * objects by an enum key of the {@link Property} type.
- *
  */
 public interface IPropertyContainer {
 

layout/src/main/java/com/itextpdf/layout/element/Paragraph.java

@@ -112,7 +112,7 @@ public Paragraph add(ILeafElement element) {
      * @param elements the content to be added, any {@link ILeafElement}
      * @return this Paragraph
      */
-    public Paragraph addAll(java.util.List<? extends ILeafElement> elements) {
+    public <T2 extends ILeafElement> Paragraph addAll(java.util.List<T2> elements) {
         for (ILeafElement element : elements) {
             add(element);
         }

layout/src/main/java/com/itextpdf/layout/renderer/BlockRenderer.java

@@ -437,8 +437,6 @@ private Point getLayoutShiftAndRotatedPoints(List<Point> rotatedPoints, float sh
         return new Point(dx, dy);
     }
 
-
-
     protected void beginRotationIfApplied(PdfCanvas canvas) {
         Float angle = getPropertyAsFloat(Property.ROTATION_ANGLE);
         if (angle != null) {

layout/src/main/java/com/itextpdf/layout/renderer/DocumentRenderer.java

@@ -148,5 +148,4 @@ private void moveToNextPage() {
         }
         currentPageNumber++;
     }
-
 }

layout/src/main/java/com/itextpdf/layout/renderer/RootRenderer.java

@@ -125,6 +125,7 @@ public void addChild(IRenderer renderer) {
                 renderer = result.getOverflowRenderer();
             }
             if (currentArea != null) {
+                assert result != null && result.getOccupiedArea() != null;
                 currentArea.getBBox().setHeight(currentArea.getBBox().getHeight() - result.getOccupiedArea().getBBox().getHeight());
                 currentArea.setEmptyArea(false);
                 if (renderer != null) {

layout/src/main/java/com/itextpdf/layout/renderer/TextRenderer.java

@@ -884,7 +884,6 @@ protected float calculateLineWidth() {
     /**
      * This method return a LinkedHashMap with glyphlines as its keys. Values are boolean flags indicating if a
      * glyphline is written in a reversed order (right to left text).
-     * @return
      */
     private Map<GlyphLine, Boolean> getOutputChunks() {
         List<int[]> reversedRange = getProperty(Property.REVERSED);