Add LineArrow name constant

During updating samples, it was found out that LineArrow name
isn't added as constant in PdfName class, though LineArrow name
is described in the specification as one of the valid values of the IT entry.

DEVSIX-3352

Author: EvgenyB1001

kernel/src/main/java/com/itextpdf/kernel/pdf/PdfName.java

@@ -495,6 +495,7 @@ public class PdfName extends PdfPrimitiveObject implements Comparable<PdfName> {
     public static final PdfName Lighten = createDirectName("Lighten");
     public static final PdfName Limits = createDirectName("Limits");
     public static final PdfName Line = createDirectName("Line");
+    public static final PdfName LineArrow = createDirectName("LineArrow");
     public static final PdfName LineHeight = createDirectName("LineHeight");
     public static final PdfName LineNum = createDirectName("LineNum");
     public static final PdfName LineThrough = createDirectName("LineThrough");