Made ImDrawCallback_ResetRenderState special value -8 instead of -1 so it is pointer aligned (#6969)

note https://github.com/dearimgui/dear_bindings/issues/56 may not be of direct use as-i.

imgui.h

@@ -2540,9 +2540,9 @@ typedef void (*ImDrawCallback)(const ImDrawList* parent_list, const ImDrawCmd* c
 
 // Special Draw callback value to request renderer backend to reset the graphics/render state.
 // The renderer backend needs to handle this special value, otherwise it will crash trying to call a function at this address.
-// This is useful for example if you submitted callbacks which you know have altered the render state and you want it to be restored.
-// It is not done by default because they are many perfectly useful way of altering render state for imgui contents (e.g. changing shader/blending settings before an Image call).
-#define ImDrawCallback_ResetRenderState     (ImDrawCallback)(-1)
+// This is useful, for example, if you submitted callbacks which you know have altered the render state and you want it to be restored.
+// Render state is not reset by default because they are many perfectly useful way of altering render state (e.g. changing shader/blending settings before an Image call).
+#define ImDrawCallback_ResetRenderState     (ImDrawCallback)(-8)
 
 // Typically, 1 command = 1 GPU draw call (unless command is a callback)
 // - VtxOffset: When 'io.BackendFlags & ImGuiBackendFlags_RendererHasVtxOffset' is enabled,