traces: always print the reduced grammar and fix it

* src/gram.c (grammar_dump): Print the effective number first instead
of last.  And fix it (remove the incorrect "+1").
Use t/f for Booleans.
* src/reduce.c: When asked, always print the reduced grammar, even if
there was nothing useless.
* tests/sets.at (Reduced Grammar): Check that.

tests/sets.at

@@ -300,3 +300,63 @@ AT_CHECK([sed -n '
         0, [expout])
 
 AT_CLEANUP
+
+
+
+## ----------------- ##
+## Reduced Grammar.  ##
+## ----------------- ##
+
+# Check information about the grammar, once reduced.
+
+AT_SETUP([Reduced Grammar])
+
+AT_DATA([input.y],
+[[%%
+expr: expr "+" term | term
+term: term "*" fact | fact
+fact: "num"
+]])
+
+AT_BISON_CHECK([[--trace=grammar -o input.c input.y]], [], [],
+[[Reduced Grammar
+
+ntokens = 6, nvars = 4, nsyms = 10, nrules = 6, nritems = 17
+
+Variables
+---------
+
+Value  Sprec  Sassoc  Tag
+    6      0       0  $accept
+    7      0       0  expr
+    8      0       0  term
+    9      0       0  fact
+
+
+Rules
+-----
+
+Num (Num, Prec, Assoc, Useful, UselessChain, Ritem Range) Lhs -> Rhs (Ritem range)
+  0 (  0,  0,  0,  t,  0- 1)    6 ->   7   0
+  1 (  1,  0,  0,  t,  3- 5)    7 ->   7   3   8
+  2 (  2,  0,  0,  t,  7- 7)    7 ->   8
+  3 (  3,  0,  0,  t,  9-11)    8 ->   8   4   9
+  4 (  4,  0,  0,  t, 13-13)    8 ->   9
+  5 (  5,  0,  0,  t, 15-15)    9 ->   5
+
+
+Rules interpreted
+-----------------
+
+0      $accept: expr $end
+1      expr: expr "+" term
+2      expr: term
+3      term: term "*" fact
+4      term: fact
+5      fact: "num"
+
+
+reduced input.y defines 6 terminals, 4 nonterminals, and 6 productions.
+]])
+
+AT_CLEANUP