tailcfg: fix typo in SessionDuration field name

Noted by @danderson.

Updates #3802

Change-Id: Ide15f3f28e30f6abb5c94d7dcd218bd9482752a0
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

ssh/tailssh/tailssh.go

@@ -797,10 +797,10 @@ func (ss *sshSession) run() {
 
 	defer ss.ctx.CloseWithError(errSessionDone)
 
-	if ss.action.SesssionDuration != 0 {
-		t := time.AfterFunc(ss.action.SesssionDuration, func() {
+	if ss.action.SessionDuration != 0 {
+		t := time.AfterFunc(ss.action.SessionDuration, func() {
 			ss.ctx.CloseWithError(userVisibleError{
-				fmt.Sprintf("Session timeout of %v elapsed.", ss.action.SesssionDuration),
+				fmt.Sprintf("Session timeout of %v elapsed.", ss.action.SessionDuration),
 				context.DeadlineExceeded,
 			})
 		})

tailcfg/tailcfg.go

@@ -1730,9 +1730,9 @@ type SSHAction struct {
 	// without further prompts.
 	Accept bool `json:"accept,omitempty"`
 
-	// SesssionDuration, if non-zero, is how long the session can stay open
+	// SessionDuration, if non-zero, is how long the session can stay open
 	// before being forcefully terminated.
-	SesssionDuration time.Duration `json:"sessionDuration,omitempty"`
+	SessionDuration time.Duration `json:"sessionDuration,omitempty"`
 
 	// AllowAgentForwarding, if true, allows accepted connections to forward
 	// the ssh agent if requested.