runtime/metrics: fix a couple of documentation typpos

Fixes #44150

Change-Id: Ibe5bfba01491dd8c2f0696fab40a1673230d76e9
Reviewed-on: https://go-review.googlesource.com/c/go/+/290349
Trust: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>

src/runtime/metrics/doc.go

@@ -16,13 +16,14 @@ Interface
 Metrics are designated by a string key, rather than, for example, a field name in
 a struct. The full list of supported metrics is always available in the slice of
 Descriptions returned by All. Each Description also includes useful information
-about the metric, such as how to display it (e.g. gauge vs. counter) and how difficult
+about the metric, such as how to display it (for example, gauge vs. counter)
-or disruptive it is to obtain it (e.g. do you need to stop the world?).
+and how difficult or disruptive it is to obtain it (for example, do you need to
+stop the world?).
 
 Thus, users of this API are encouraged to sample supported metrics defined by the
 slice returned by All to remain compatible across Go versions. Of course, situations
 arise where reading specific metrics is critical. For these cases, users are
-encouranged to use build tags, and although metrics may be deprecated and removed,
+encouraged to use build tags, and although metrics may be deprecated and removed,
 users should consider this to be an exceptional and rare event, coinciding with a
 very large change in a particular Go implementation.
 

src/runtime/metrics/sample.go

@@ -32,9 +32,9 @@ func runtime_readMetrics(unsafe.Pointer, int, int)
 //
 // Note that re-use has some caveats. Notably, Values should not be read or
 // manipulated while a Read with that value is outstanding; that is a data race.
-// This property includes pointer-typed Values (e.g. Float64Histogram) whose
+// This property includes pointer-typed Values (for example, Float64Histogram)
-// underlying storage will be reused by Read when possible. To safely use such
+// whose underlying storage will be reused by Read when possible. To safely use
-// values in a concurrent setting, all data must be deep-copied.
+// such values in a concurrent setting, all data must be deep-copied.
 //
 // It is safe to execute multiple Read calls concurrently, but their arguments
 // must share no underlying memory. When in doubt, create a new []Sample from

src/runtime/metrics/value.go

@@ -33,7 +33,7 @@ type Value struct {
 	pointer unsafe.Pointer // contains non-scalar values.
 }
 
-// Kind returns the a tag representing the kind of value this is.
+// Kind returns the tag representing the kind of value this is.
 func (v Value) Kind() ValueKind {
 	return v.kind
 }