doc: edit documentation that uses "satisfies reads" and "satisfies writes"

Make it clear that types that wrap another reader or writer delegate to the wrapped type.

Fixes #7667

LGTM=adg
R=golang-codereviews, adg
CC=golang-codereviews
https://golang.org/cl/85720044

src/pkg/compress/gzip/gzip.go

@@ -22,8 +22,8 @@ const (
 	DefaultCompression = flate.DefaultCompression
 )
 
-// A Writer is an io.WriteCloser that satisfies writes by compressing data written
-// to its wrapped io.Writer.
+// A Writer is an io.WriteCloser.
+// Writes to a Writer are compressed and written to w.
 type Writer struct {
 	Header
 	w           io.Writer
@@ -37,8 +37,8 @@ type Writer struct {
 	err         error
 }
 
-// NewWriter creates a new Writer that satisfies writes by compressing data
-// written to w.
+// NewWriter returns a new Writer.
+// Writes to the returned writer are compressed and written to w.
 //
 // It is the caller's responsibility to call Close on the WriteCloser when done.
 // Writes may be buffered and not flushed until Close.

src/pkg/compress/lzw/reader.go

@@ -216,8 +216,8 @@ func (d *decoder) Close() error {
 	return nil
 }
 
-// NewReader creates a new io.ReadCloser that satisfies reads by decompressing
-// the data read from r.
+// NewReader creates a new io.ReadCloser.
+// Reads from the returned io.ReadCloser read and decompress data from r.
 // It is the caller's responsibility to call Close on the ReadCloser when
 // finished reading.
 // The number of bits to use for literal codes, litWidth, must be in the

src/pkg/compress/lzw/writer.go

@@ -225,8 +225,8 @@ func (e *encoder) Close() error {
 	return e.w.Flush()
 }
 
-// NewWriter creates a new io.WriteCloser that satisfies writes by compressing
-// the data and writing it to w.
+// NewWriter creates a new io.WriteCloser.
+// Writes to the returned io.WriteCloser are compressed and written to w.
 // It is the caller's responsibility to call Close on the WriteCloser when
 // finished writing.
 // The number of bits to use for literal codes, litWidth, must be in the

src/pkg/compress/zlib/reader.go

@@ -51,7 +51,8 @@ type reader struct {
 	scratch      [4]byte
 }
 
-// NewReader creates a new io.ReadCloser that satisfies reads by decompressing data read from r.
+// NewReader creates a new io.ReadCloser.
+// Reads from the returned io.ReadCloser read and decompress data from r.
 // The implementation buffers input and may read more data than necessary from r.
 // It is the caller's responsibility to call Close on the ReadCloser when done.
 func NewReader(r io.Reader) (io.ReadCloser, error) {

src/pkg/compress/zlib/writer.go

@@ -34,8 +34,8 @@ type Writer struct {
 	wroteHeader bool
 }
 
-// NewWriter creates a new Writer that satisfies writes by compressing data
-// written to w.
+// NewWriter creates a new Writer.
+// Writes to the returned Writer are compressed and written to w.
 //
 // It is the caller's responsibility to call Close on the WriteCloser when done.
 // Writes may be buffered and not flushed until Close.