CDocTemplate::GetDocString

关于CDocTemplate中各个字符串段的含义mark一下：

可以在Stringtable中相应的IDRXXXTYPE中修改相应字段

enum DocStringIndex{    windowTitle,        // default window title    docName,            // user visible name for default document    fileNewName,        // user visible name for FileNew    // for file based documents:    filterName,         // user visible name for FileOpen    filterExt,          // user visible extension for FileOpen    // for file based documents with Shell open support:    regFileTypeId,      // REGEDIT visible registered file type identifier    regFileTypeName,    // Shell visible registered file type name};