all: fix some minor grammatical issues in the comments

Change-Id: I0459f05e7f6abd9738813c65d993114e931720d5
Reviewed-on: https://go-review.googlesource.com/c/go/+/731000
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
Auto-Submit: Keith Randall <khr@golang.org>

src/archive/tar/reader_test.go

@@ -787,7 +787,7 @@ type readBadSeeker struct{ io.ReadSeeker }
 
 func (rbs *readBadSeeker) Seek(int64, int) (int64, error) { return 0, fmt.Errorf("illegal seek") }
 
-// TestReadTruncation test the ending condition on various truncated files and
+// TestReadTruncation tests the ending condition on various truncated files and
 // that truncated files are still detected even if the underlying io.Reader
 // satisfies io.Seeker.
 func TestReadTruncation(t *testing.T) {

src/archive/tar/stat_unix.go

@@ -19,7 +19,7 @@ func init() {
 	sysStat = statUnix
 }
 
-// userMap and groupMap caches UID and GID lookups for performance reasons.
+// userMap and groupMap cache UID and GID lookups for performance reasons.
 // The downside is that renaming uname or gname by the OS never takes effect.
 var userMap, groupMap sync.Map // map[int]string
 

src/archive/tar/strconv.go

@@ -312,7 +312,7 @@ func formatPAXRecord(k, v string) (string, error) {
 //	"%d %s=%s\n" % (size, key, value)
 //
 // Keys and values should be UTF-8, but the number of bad writers out there
-// forces us to be a more liberal.
+// forces us to be more liberal.
 // Thus, we only reject all keys with NUL, and only reject NULs in values
 // for the PAX version of the USTAR string fields.
 // The key must not contain an '=' character.

src/runtime/trace.go

@@ -12,7 +12,7 @@
 //
 // ## Design
 //
-// The basic idea behind the the execution tracer is to have per-M buffers that
+// The basic idea behind the execution tracer is to have per-M buffers that
 // trace data may be written into. Each M maintains a write flag indicating whether
 // its trace buffer is currently in use.
 //
@@ -173,7 +173,7 @@
 // doesn't do this directly for performance reasons. The runtime implementation instead caches
 // a G on the M created for the C thread. On Linux this M is then cached in the thread's TLS,
 // and on other systems, the M is put on a global list on exit from Go. We need to do some
-// extra work to make sure that this is modeled correctly in the the tracer. For example,
+// extra work to make sure that this is modeled correctly in the tracer. For example,
 // a C thread exiting Go may leave a P hanging off of its M (whether that M is kept in TLS
 // or placed back on a list). In order to correctly model goroutine creation and destruction,
 // we must behave as if the P was at some point stolen by the runtime, if the C thread

src/runtime/tracebuf.go

@@ -29,7 +29,7 @@ type traceWriter struct {
 	*traceBuf
 }
 
-// writer returns an a traceWriter that writes into the current M's stream.
+// writer returns a traceWriter that writes into the current M's stream.
 //
 // Once this is called, the caller must guard against stack growth until
 // end is called on it. Therefore, it's highly recommended to use this

test/typeparam/typelist.go

@@ -32,7 +32,7 @@ func _[T interface{ ~int }](x T) {
 	var _ T = T(myint(42))
 }
 
-// Indexing a generic type which has a an array as core type.
+// Indexing a generic type which has an array as core type.
 func _[T interface{ ~[10]int }](x T) {
 	_ = x[9] // ok
 }