Cast this to (void*) in zero-clearing memset calls to fix -Wnontrivial-memcall. Amends for docking (#9247, #8295, #8129, #8135)

diff --git a/imgui.cpp b/imgui.cpp
index aa23213..29b7f8c 100644
--- a/imgui.cpp
+++ b/imgui.cpp

@@ -17630,7 +17630,7 @@
     ImVec2ih            Pos;
     ImVec2ih            Size;
     ImVec2ih            SizeRef;
-    ImGuiDockNodeSettings() { memset(this, 0, sizeof(*this)); SplitAxis = ImGuiAxis_None; }
+    ImGuiDockNodeSettings() { memset((void*)this, 0, sizeof(*this)); SplitAxis = ImGuiAxis_None; }
 };
 
 //-----------------------------------------------------------------------------
@@ -18662,7 +18662,7 @@
     int                 CountNodesWithWindows;
     //ImGuiWindowClass  WindowClassForMerges;
 
-    ImGuiDockNodeTreeInfo() { memset(this, 0, sizeof(*this)); }
+    ImGuiDockNodeTreeInfo() { memset((void*)this, 0, sizeof(*this)); }
 };
 
 static void DockNodeFindInfo(ImGuiDockNode* node, ImGuiDockNodeTreeInfo* info)

diff --git a/imgui.h b/imgui.h
index a4424e0..a39652d 100644
--- a/imgui.h
+++ b/imgui.h

@@ -2804,7 +2804,7 @@
     bool                DockingAlwaysTabBar;        // Set to true to enforce single floating windows of this class always having their own docking node (equivalent of setting the global io.ConfigDockingAlwaysTabBar)
     bool                DockingAllowUnclassed;      // Set to true to allow windows of this class to be docked/merged with an unclassed window. // FIXME-DOCK: Move to DockNodeFlags override?
 
-    ImGuiWindowClass() { memset(this, 0, sizeof(*this)); ParentViewportId = (ImGuiID)-1; DockingAllowUnclassed = true; }
+    ImGuiWindowClass() { memset((void*)this, 0, sizeof(*this)); ParentViewportId = (ImGuiID)-1; DockingAllowUnclassed = true; }
 };
 
 // Data payload for Drag and Drop operations: AcceptDragDropPayload(), GetDragDropPayload()

diff --git a/imgui_internal.h b/imgui_internal.h
index e23bd23..b1904de 100644
--- a/imgui_internal.h
+++ b/imgui_internal.h

@@ -2115,7 +2115,7 @@
     ImVector<ImGuiDockRequest>      Requests;
     ImVector<ImGuiDockNodeSettings> NodesSettings;
     bool                            WantFullRebuild;
-    ImGuiDockContext()              { memset(this, 0, sizeof(*this)); }
+    ImGuiDockContext()              { memset((void*)this, 0, sizeof(*this)); }
 };
 
 #endif // #ifdef IMGUI_HAS_DOCK