testing: use conventional comments for exported internal funcs & structs

Change-Id: I2dd5ddc22bfff143b81d5945992d8c5fccf387f4
GitHub-Last-Rev: aa637756e772f5ee9094b802df3be9945c8466c4
GitHub-Pull-Request: golang/go#36054
Reviewed-on: https://go-review.googlesource.com/c/go/+/210497Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/testing/benchmark.go

@@ -69,8 +69,8 @@ var benchmarkLock sync.Mutex
 // Used for every benchmark for measuring memory.
 var memStats runtime.MemStats
 
-// An internal type but exported because it is cross-package; part of the implementation
-// of the "go test" command.
+// InternalBenchmark is an internal type but exported because it is cross-package;
+// it is part of the implementation of the "go test" command.
 type InternalBenchmark struct {
 	Name string
 	F    func(b *B)
@@ -342,7 +342,7 @@ func (b *B) ReportMetric(n float64, unit string) {
 	b.extra[unit] = n
 }
 
-// The results of a benchmark run.
+// BenchmarkResult contains the results of a benchmark run.
 type BenchmarkResult struct {
 	N         int           // The number of iterations.
 	T         time.Duration // The total time taken.
@@ -488,8 +488,8 @@ type benchContext struct {
 	extLen int // Maximum extension length.
 }
 
-// An internal function but exported because it is cross-package; part of the implementation
-// of the "go test" command.
+// RunBenchmarks is an internal function but exported because it is cross-package;
+// it is part of the implementation of the "go test" command.
 func RunBenchmarks(matchString func(pat, str string) (bool, error), benchmarks []InternalBenchmark) {
 	runBenchmarks("", matchString, benchmarks)
 }

src/testing/example.go

@@ -19,8 +19,8 @@ type InternalExample struct {
 	Unordered bool
 }
 
-// An internal function but exported because it is cross-package; part of the implementation
-// of the "go test" command.
+// RunExamples is an internal function but exported because it is cross-package;
+// it is part of the implementation of the "go test" command.
 func RunExamples(matchString func(pat, str string) (bool, error), examples []InternalExample) (ok bool) {
 	_, ok = runExamples(matchString, examples)
 	return ok

src/testing/testing.go

@@ -863,8 +863,8 @@ func (t *T) Parallel() {
 	t.raceErrors += -race.Errors()
 }
 
-// An internal type but exported because it is cross-package; part of the implementation
-// of the "go test" command.
+// InternalTest is an internal type but exported because it is cross-package;
+// it is part of the implementation of the "go test" command.
 type InternalTest struct {
 	Name string
 	F    func(*T)
@@ -1214,8 +1214,8 @@ func listTests(matchString func(pat, str string) (bool, error), tests []Internal
 	}
 }
 
-// An internal function but exported because it is cross-package; part of the implementation
-// of the "go test" command.
+// RunTests is an internal function but exported because it is cross-package;
+// it is part of the implementation of the "go test" command.
 func RunTests(matchString func(pat, str string) (bool, error), tests []InternalTest) (ok bool) {
 	ran, ok := runTests(matchString, tests)
 	if !ran && !haveExamples {