Informs the host that the scripting engine has returned from executing script code.
Returns S_OK if successful.
The scripting engine must call this method before returning control to a calling application that entered the scripting engine. For example, if the script calls an object that then fires an event handled by the scripting engine, the scripting engine must call the IActiveScriptSite::OnEnterScript method before executing the event, and must call IActiveScriptSite::OnLeaveScript after executing the event before returning to the object that fired the event. Calls to this method can be nested. Every call to IActiveScriptSite::OnEnterScript requires a corresponding call to this method.