py: Update parse.c&mpconfig.h to reflect rename of mp_lexer_show_token.

This function is only used when DEBUG_PRINTERS and USE_RULE_NAME are
enabled.

py/mpconfig.h

@@ -178,7 +178,7 @@
 #endif
 
 // Whether to build functions that print debugging info:
-//   mp_token_show
+//   mp_lexer_show_token
 //   mp_bytecode_print
 //   mp_parse_node_print
 #ifndef MICROPY_DEBUG_PRINTERS

py/parse.c

@@ -782,7 +782,7 @@ syntax_error:
         // debugging: print the rule name that failed and the token
         printf("rule: %s\n", rule->rule_name);
 #if MICROPY_DEBUG_PRINTERS
-        mp_token_show(lex);
+        mp_lexer_show_token(lex);
 #endif
 #endif
     }