style: don't use std::endl

* data/lalr1.cc, doc/bison.texi, etc/bench.pl.in, examples/variant.yy,
* tests/actions.at, tests/atlocal.in, tests/c++.at, tests/headers.at,
* tests/local.at, tests/types.at:
Don't use std::endl, it flushes uselessly, and is considered bad
style.

tests/types.at

@@ -243,7 +243,7 @@ m4_foreach([b4_skel], [[yacc.c], [glr.c], [lalr1.cc], [glr.cc]],
            %define api.value.type variant],
           [%token <int> '1';
            %token <std::string> '2';],
-          ['1' '2' { std::cout << $1 << ", " << $2 << std::endl; }],
+          ['1' '2' { std::cout << $1 << ", " << $2 << '\n'; }],
           ["12"],
           [if (res == '1')
              AT_VAL.build(10);