clean up code formatting (purely cosmetic)

	modified:   src/base/assert_true.h
	modified:   src/base/backoff_rate_limiter.cc
	modified:   src/base/backoff_rate_limiter.h
	modified:   src/base/code_location.cc
	modified:   src/base/code_location.h
	modified:   src/base/convert.h
	modified:   src/base/convert.test.cc
	modified:   src/base/demangle.cc
	modified:   src/base/demangle.h
	modified:   src/base/dir_iter.cc
	modified:   src/base/dir_iter.h
	modified:   src/base/error.cc
	modified:   src/base/error.h
	modified:   src/base/error.test.cc
	modified:   src/base/error_utils.h
	modified:   src/base/error_utils.test.cc
	modified:   src/base/event_semaphore.h
	modified:   src/base/event_semaphore.test.cc
	modified:   src/base/fd.h
	modified:   src/base/impossible_error.h
	modified:   src/base/indent.h
	modified:   src/base/indent.test.cc
	modified:   src/base/io_utils.cc
	modified:   src/base/io_utils.h
	modified:   src/base/io_utils.test.cc
	modified:   src/base/no_construction.h
	modified:   src/base/no_default_case.h
	modified:   src/base/not_found_error.h
	modified:   src/base/ofdstream.h
	modified:   src/base/opt.h
	modified:   src/base/os_error.h
	modified:   src/base/piece.cc
	modified:   src/base/piece.h
	modified:   src/base/pos.cc
	modified:   src/base/pos.h
	modified:   src/base/safe_global.h
	modified:   src/base/slice.cc
	modified:   src/base/slice.h
	modified:   src/base/spin_lock.h
	modified:   src/base/stl_utils.h
	modified:   src/base/syntax_error.h
	modified:   src/base/thrower.cc
	modified:   src/base/thrower.h
	modified:   src/base/time.cc
	modified:   src/base/time.h
	modified:   src/base/timer_fd.cc
	modified:   src/base/timer_fd.h
	modified:   src/base/tmp_dir.h
	modified:   src/base/tmp_file.h
	modified:   src/base/tmp_file_name.h
	modified:   src/base/zero.h