Use $accept and $end, as BYacc and BTYacc do, instead of $axiom and $.

* src/symtab.h, src/symtab.c (eoftoken, axiom): Rename as...
(endtoken, accept): these.
* src/reader.c (reader): Set endtoken's default tag to "$end".
Set undeftoken's tag to "$undefined" instead of "$undefined.".
* doc/bison.texinfo (Table of Symbols): Mention $accept and $end.
Adjust.

src/state.c

@@ -122,7 +122,7 @@ reductions_new (int num, rule_number_t *reductions)
 
 state_number_t nstates = 0;
 /* FINAL_STATE is properly set by new_state when it recognizes its
-   accessing symbol: EOF.  */
+   accessing symbol: $end.  */
 state_t *final_state = NULL;
 
 #define STATE_ALLOC(Nitems)						\