Increase width of 'Attributes' window

Before this change some lines in the "Advanced Options" window would not
fit into one line and would screw up the others. This depends on the fonts
used, but increasing the width of the panel a bit does not hurt.

src/winspector.c

@@ -158,7 +158,7 @@ static WMPropList *AnyWindow;
 static WMPropList *EmptyString;
 static WMPropList *Yes, *No;
 
-#define PWIDTH	270
+#define PWIDTH	290
 #define PHEIGHT	350
 
 static char *spec_text;