fix ChangeInvalidFileNameChars

Source/ksString.pas

@@ -167,9 +167,8 @@ begin
     Ch := PFileName[I];
 
     if not TPath.IsValidFileNameChar(Ch) then
-      PFileName[I] := AChar
-    else
-      Inc(I);
+      PFileName[I] := AChar;
+    Inc(I);
   end;
 end;