gdiplus: Fix default value of StringTrimmingCharacter.

dlls/gdiplus/stringformat.c

@@ -40,6 +40,7 @@ GpStatus WINGDIPAPI GdipCreateStringFormat(INT attr, LANGID lang,
 
     (*format)->attr = attr;
     (*format)->lang = lang;
+    (*format)->trimming = StringTrimmingCharacter;
 
     return Ok;
 }

dlls/gdiplus/tests/stringformat.c

@@ -43,8 +43,7 @@ static void test_constructor(void)
     expect(HotkeyPrefixNone, n);
     expect(StringAlignmentNear, align);
     expect(StringAlignmentNear, align);
-    todo_wine
-        expect(StringTrimmingCharacter, trimming);
+    expect(StringTrimmingCharacter, trimming);
 
     stat = GdipDeleteStringFormat(format);
     expect(Ok, stat);