feat(ui): implement CSimpleEditBox_SetFocus

src/ui/CSimpleEditBoxScript.cpp

@@ -176,7 +176,12 @@ int32_t CSimpleEditBox_GetTextInsets(lua_State* L) {
 }
 
 int32_t CSimpleEditBox_SetFocus(lua_State* L) {
-    WHOA_UNIMPLEMENTED(0);
+    auto type = CSimpleEditBox::GetObjectType();
+    auto editBox = static_cast<CSimpleEditBox*>(FrameScript_GetObjectThis(L, type));
+
+    CSimpleEditBox::SetKeyboardFocus(editBox);
+
+    return 0;
 }
 
 int32_t CSimpleEditBox_ClearFocus(lua_State* L) {