Make Unicode strings static const.

diff --git a/dlls/comctl32/treeview.c b/dlls/comctl32/treeview.c
index 9d6880d..00d0c54 100644
--- a/dlls/comctl32/treeview.c
+++ b/dlls/comctl32/treeview.c
@@ -3467,7 +3467,7 @@
     HDC hdc;
     HFONT hOldFont=0;
     TEXTMETRICW textMetric;
-    WCHAR EditW[] = {'E','d','i','t',0};
+    static const WCHAR EditW[] = {'E','d','i','t',0};
 
     TRACE("%x %p\n", (unsigned)hwnd, hItem);
     if (!TREEVIEW_ValidItem(infoPtr, editItem))