Switch to StringBuffer for c#-porting reasons. Minor refactroing.

Autoported commit.
Original commit hash: [a5659783e]

Author: ars18wrw

itext/itext.forms/itext/forms/fields/PdfFormField.cs

@@ -3905,23 +3905,23 @@ private void ApplyRotation(PdfFormXObject xObject, float height, float width) {
         }
 
         private static String OptionsArrayToString(PdfArray options) {
-            StringBuilder stringBuilder = new StringBuilder();
+            StringBuilder stringBuffer = new StringBuilder();
             foreach (PdfObject obj in options) {
                 if (obj.IsString()) {
-                    stringBuilder.Append(((PdfString)obj).ToUnicodeString()).Append('\n');
+                    stringBuffer.Append(((PdfString)obj).ToUnicodeString()).Append('\n');
                 }
                 else {
                     if (obj.IsArray()) {
                         PdfObject element = ((PdfArray)obj).Get(1);
                         if (element.IsString()) {
-                            stringBuilder.Append(((PdfString)element).ToUnicodeString()).Append('\n');
+                            stringBuffer.Append(((PdfString)element).ToUnicodeString()).Append('\n');
                         }
                     }
                 }
             }
-            stringBuilder.DeleteCharAt(stringBuilder.Length - 1);
+            stringBuffer.DeleteCharAt(stringBuffer.Length - 1);
             // last '\n'
-            return stringBuilder.ToString();
+            return stringBuffer.ToString();
         }
 
         private static double DegreeToRadians(double angle) {

port-hash

@@ -1 +1 @@
-363b7cef71502f37c19acba57e1abca4fd3ea494
+a5659783ef61b5269074a10ac81b1e44e2ed83e8