all: fix more typos caused by unnecessary repetition

Updates #cleanup

Change-Id: I5c0b8f0152581231252ab97dd1820d8b3fcbe450
Signed-off-by: Alex Chan <alexc@tailscale.com>

net/dns/manager.go

@@ -522,7 +522,7 @@ const (
 	maxReqSizeTCP = 4096
 )
 
-// TrampleDNS is an an event indicating we detected that DNS config was
+// TrampleDNS is an event indicating we detected that DNS config was
 // overwritten by another process.
 type TrampleDNS struct {
 	LastTrample       time.Time

net/stun/stun.go

@@ -211,8 +211,8 @@ func ParseResponse(b []byte) (tID TxID, addr netip.AddrPort, err error) {
 	var fallbackAddr netip.AddrPort
 
 	// Read through the attributes.
-	// The the addr+port reported by XOR-MAPPED-ADDRESS
-	// as the canonical value. If the attribute is not
+	// The addr+port reported by XOR-MAPPED-ADDRESS
+	// is the canonical value. If the attribute is not
 	// present but the STUN server responds with
 	// MAPPED-ADDRESS we fall back to it.
 	if err := foreachAttr(b, func(attrType uint16, attr []byte) error {