all: fix typos where we repeat repeat ourselves

Found with the regex `\b([A-Za-z]+) \1\b`.

Updates #cleanup

Change-Id: I4cc51784d9b6437d3d0c66b531828707f87f7fd5
Signed-off-by: Alex Chan <alexc@tailscale.com>

ipn/ipnlocal/local.go

@@ -784,7 +784,7 @@ func (b *LocalBackend) onHomeDERPUpdate(du magicsock.HomeDERPChanged) {
 // In practice, it is possible that one profile with a homeDERP of 0 (no-derp)
 // got switched before setting any home DERP or that DERP IDs match across
 // DERP maps. Since the risk of this happening is small and the consequences
-// of this is is just a possible less optimal DERP until the next reSTUN,
+// of this is just a possible less optimal DERP until the next reSTUN,
 // accept this possibility.
 func (b *LocalBackend) onHomeDERPUpdateLocked(du magicsock.HomeDERPChanged) {
 	cn := b.currentNode()

ipn/ipnlocal/local_test.go

@@ -8301,7 +8301,7 @@ func TestDisplayMessageIPNBus(t *testing.T) {
 					if ok {
 						if diff := cmp.Diff(tt.wantWarning, got, cmpopts.IgnoreFields(health.UnhealthyState{}, "ETag")); diff != "" {
 							t.Errorf("unexpected warning details (-want/+got):\n%s", diff)
-							return true // we failed the test so tell the watcher we've seen what we need to to stop it waiting
+							return true // we failed the test so tell the watcher we've seen what we need to stop it waiting
 						}
 					} else {
 						got := slices.Collect(maps.Keys(n.Health.Warnings))

ipn/ipnstate/ipnstate.go

@@ -137,7 +137,7 @@ type TailnetLockStatus struct {
 	TrustedKeys []TKAKey
 
 	// VisiblePeers describes peers which are visible in the netmap that
-	// have valid Tailnet Lock signatures signatures.
+	// have valid Tailnet Lock signatures.
 	VisiblePeers []*TKAPeer
 
 	// FilteredPeers describes peers which were removed from the netmap

ipn/localapi/cert.go

@@ -40,7 +40,7 @@ func (h *Handler) serveCert(w http.ResponseWriter, r *http.Request) {
 	pair, err := h.b.GetCertPEMWithValidity(r.Context(), domain, minValidity)
 	if err != nil {
 		// TODO(bradfitz): 500 is a little lazy here. The errors returned from
-		// GetCertPEM (and everywhere) should carry info info to get whether
+		// GetCertPEM (and everywhere) should carry info to get whether
 		// they're 400 vs 403 vs 500 at minimum. And then we should have helpers
 		// (in tsweb probably) to return an error that looks at the error value
 		// to determine the HTTP status code.

ipn/store/awsstore/store_aws.go

@@ -79,7 +79,7 @@ type awsStore struct {
 //
 // Note that we store the entire store in a single parameter
 // key, therefore if the state is above 8kb, it can cause
-// Tailscaled to only only store new state in-memory and
+// Tailscaled to only store new state in-memory and
 // restarting Tailscaled can fail until you delete your state
 // from the AWS Parameter Store.
 //