OO-4602: escape special - from windows

src/main/java/org/olat/core/util/pdf/PdfDocument.java

@@ -217,7 +217,11 @@ public class PdfDocument {
     }
     
     public static String cleanString(String string) {
-    	return string.replace('\n', ' ').replace('\r', ' ').replace('\t', ' ').replace('\u00A0', ' ');
+    	return string.replace('\n', ' ')
+    			.replace('\r', ' ')
+    			.replace('\t', ' ')
+    			.replace('\u00A0', ' ')
+    			.replace('\u2212', '-');
     }
     
     public void drawLine(float xStart, float yStart, float xEnd, float yEnd, float lineWidth) 

src/test/java/org/olat/core/util/pdf/PdfDocumentTest.java

@@ -48,7 +48,8 @@ public class PdfDocumentTest {
                 { "Hello\tworld", "Hello world" },
                 { "Hello\n\tworld", "Hello  world" },
                 { "Hello\n\tworld\u00A0", "Hello  world " },
-                { "Hello \u3044", "Hello \u3044" }
+                { "Hello \u3044", "Hello \u3044" },
+                { "Hello \u2212", "Hello -" }
         });
     }