Wrap long usage message

Turns out Cobra doesn't wrap usage messages, so they look pretty ugly if
we don't pick a pretty conservative width and wrap by hand.

cmd/foreach/foreach.go

@@ -49,10 +49,10 @@ func NewForeachCmd() *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "foreach [--repos REPOFILE] -- COMMAND [ARGUMENT...]",
 		Short: "Run COMMAND against each working copy",
-		Long: "Run COMMAND against each working copy. " +
-			"Make sure to include a double hyphen -- with space on " +
-			"both sides before COMMAND, as this marks that no " +
-			"further options should be interpreted by turbolift.",
+		Long:
+`Run COMMAND against each working copy. Make sure to include a
+double hyphen -- with space on both sides before COMMAND, as this
+marks that no further options should be interpreted by turbolift.`,
 		RunE: runE,
 		Args: cobra.MinimumNArgs(1),
 	}