Fix warning + apply trailing whitespaces in stb_ libs (as applied on nothings/stb on 2020/02/02, facilitating further diffs)

imgui_draw.cpp

@@ -3206,7 +3206,7 @@ void ImFont::BuildLookupTable()
         if (FallbackGlyph == NULL)
         {
             FallbackGlyph = &Glyphs.back();
-            FallbackChar = FallbackGlyph->Codepoint;
+            FallbackChar = (ImWchar)FallbackGlyph->Codepoint;
         }
     }
 

misc/cpp/README.txt

@@ -8,3 +8,6 @@ imgui_scoped.h
   Additional header file with some RAII-style wrappers for common Dear ImGui functions.
   Try by merging: https://github.com/ocornut/imgui/pull/2197
   Discuss at: https://github.com/ocornut/imgui/issues/2096
+
+See more C++ related extension on Wiki
+  https://github.com/ocornut/imgui/wiki/Useful-Extensions#cness