Minor tweak in the package tag line.
diff --git a/tomb.go b/tomb.go
index f4b9f0b..084b530 100644
--- a/tomb.go
+++ b/tomb.go
@@ -26,7 +26,7 @@
 // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// The tomb package supports clean goroutine termination.
+// The tomb package helps with clean goroutine termination.
 //
 // See the Tomb type for details.
 package tomb