type_traits: Doxygen improvements.

type_traits: Doxygen improvements.

	* include/std/type_traits: Doxygen improvements.
	* include/bits/move.h: Likewise.
	* include/tr1/type_traits:  Likewise.
	* include/tr2/type_traits:  Likewise.
	* testsuite/20_util/declval/requirements/1_neg.cc: Adjust dg-error
	line numbers
	* testsuite/20_util/forward/c_neg.cc: Likewise.
	* testsuite/20_util/forward/f_neg.cc: Likewise.
	* testsuite/20_util/make_signed/requirements/typedefs_neg.cc:
	Likewise.
	* testsuite/20_util/make_unsigned/requirements/typedefs_neg.cc:
	Likewise.

From-SVN: r181993