all: remove duplicate articles in comment

Removed 'an an' and 'the the', 'the a' in comment.

Change-Id: I01a1f12e44bc8a2db5246e92fd83da2d7c1749e7
Reviewed-on: https://code-review.googlesource.com/c/gocloud/+/44470
Reviewed-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>

pubsub/topic.go

@@ -184,7 +184,7 @@ type TopicConfig struct {
 	// The topic's message storage policy.
 	MessageStoragePolicy MessageStoragePolicy
 
-	// The name of the the Cloud KMS key to be used to protect access to messages
+	// The name of the Cloud KMS key to be used to protect access to messages
 	// published to this topic, in the format
 	// "projects/P/locations/L/keyRings/R/cryptoKeys/K".
 	KMSKeyName string

storage/writer.go

@@ -231,7 +231,7 @@ func (w *Writer) Close() error {
 }
 
 // monitorCancel is intended to be used as a background goroutine. It monitors the
-// the context, and when it observes that the context has been canceled, it manually
+// context, and when it observes that the context has been canceled, it manually
 // closes things that do not take a context.
 func (w *Writer) monitorCancel() {
 	select {

trace/sampling.go

@@ -69,7 +69,7 @@ func (s *sampler) Sample(p Parameters) Decision {
 	return d
 }
 
-// sample contains the a deterministic, time-independent logic of Sample.
+// sample contains a deterministic, time-independent logic of Sample.
 func (s *sampler) sample(p Parameters, now time.Time, x float64) (d Decision) {
 	d.Sample = x < s.fraction
 	d.Trace = p.HasTraceHeader || d.Sample