The Defs tool window doesn't show the #endif, because it is considered to be part of the #ifdef, #ifndef, #if or #elif statement that introduced the block.
Take the following for example:
#ifdef XXXXX
void haveXXXX();
#elif YYYYY
void haveYYYYY();
#elif ZZZZZ
void haveZZZZZ();
#endif
When you turn on Statement Tagging in the Defs tool window, you will see each of the preprocessing statements, excluding the "#endif", just like we would not show the close brace for a while or for statement.
BTW, you can use the block matching to jump from a the start of a preprocessing block statement to the corresponding #endif. (Search > Go to Matching Parenthesis).