Use MessageFormatUtil for float toString conversion in UnitValue class

Autoported commit.
Original commit hash: [5e52d4dc12]

Author: yulian-gaponenko

itext/itext.layout/itext/layout/properties/UnitValue.cs

@@ -42,6 +42,7 @@ source product.
 address: [email protected]
 */
 using System;
+using iText.IO.Util;
 
 namespace iText.Layout.Properties {
     /// <summary>A specialized class that holds a value and the unit it is measured in.</summary>
@@ -198,7 +199,7 @@ public override int GetHashCode() {
         }
 
         public override String ToString() {
-            return value + (unitType == PERCENT ? "%" : "pt");
+            return MessageFormatUtil.Format((unitType == PERCENT ? "{0}%" : "{0}pt"), value);
         }
     }
 }

port-hash

@@ -1 +1 @@
-d9704561100ec2161f9b77dcc7f85170b6ac81b6
+5e52d4dc121eaca3d41608c7bcf4b4901475fc5f