Correctly read EDID on X11.

src/Avalonia.X11/X11Atoms.cs

@@ -114,7 +114,7 @@ namespace Avalonia.X11
         public readonly IntPtr XA_WM_CLASS = (IntPtr)67;
         public readonly IntPtr XA_WM_TRANSIENT_FOR = (IntPtr)68;
 
-        public readonly IntPtr RR_PROPERTY_RANDR_EDID = (IntPtr)82;
+        public readonly IntPtr EDID;
 
         public readonly IntPtr WM_PROTOCOLS;
         public readonly IntPtr WM_DELETE_WINDOW;

src/Avalonia.X11/X11Screens.cs

@@ -91,12 +91,12 @@ namespace Avalonia.X11
                 var hasEDID = false;
                 for(var pc = 0; pc < propertyCount; pc++)
                 {
-                    if(properties[pc] == _x11.Atoms.RR_PROPERTY_RANDR_EDID)
+                    if(properties[pc] == _x11.Atoms.EDID)
                         hasEDID = true;
                 }
                 if(!hasEDID)
                     return null;
-                XRRGetOutputProperty(_x11.Display, rrOutput, _x11.Atoms.RR_PROPERTY_RANDR_EDID, 0, EDIDStructureLength, false, false, _x11.Atoms.AnyPropertyType, out IntPtr actualType, out int actualFormat, out int bytesAfter, out _, out IntPtr prop);
+                XRRGetOutputProperty(_x11.Display, rrOutput, _x11.Atoms.EDID, 0, EDIDStructureLength, false, false, _x11.Atoms.AnyPropertyType, out IntPtr actualType, out int actualFormat, out int bytesAfter, out _, out IntPtr prop);
                 if(actualType != _x11.Atoms.XA_INTEGER)
                     return null;
                 if(actualFormat != 8) // Expecting an byte array