all: single space after period.

The tree's pretty inconsistent about single space vs double space
after a period in documentation. Make it consistently a single space,
per earlier decisions. This means contributors won't be confused by
misleading precedence.

This CL doesn't use go/doc to parse. It only addresses // comments.
It was generated with:

$ perl -i -npe 's,^(\s*// .+[a-z]\.)  +([A-Z]),$1 $2,' $(git grep -l -E '^\s*//(.+\.)  +([A-Z])')
$ go test go/doc -update

Change-Id: Iccdb99c37c797ef1f804a94b22ba5ee4b500c4f7
Reviewed-on: https://go-review.googlesource.com/20022
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Dave Day <djd@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/bytes/buffer.go

@@ -44,7 +44,7 @@ var ErrTooLarge = errors.New("bytes.Buffer: too large")
 func (b *Buffer) Bytes() []byte { return b.buf[b.off:] }
 
 // String returns the contents of the unread portion of the buffer
-// as a string.  If the Buffer is a nil pointer, it returns "<nil>".
+// as a string. If the Buffer is a nil pointer, it returns "<nil>".
 func (b *Buffer) String() string {
 	if b == nil {
 		// Special case, useful in debugging.
@@ -145,7 +145,7 @@ func (b *Buffer) WriteString(s string) (n int, err error) {
 }
 
 // MinRead is the minimum slice size passed to a Read call by
-// Buffer.ReadFrom.  As long as the Buffer has at least MinRead bytes beyond
+// Buffer.ReadFrom. As long as the Buffer has at least MinRead bytes beyond
 // what is required to hold the contents of r, ReadFrom will not grow the
 // underlying buffer.
 const MinRead = 512
@@ -252,7 +252,7 @@ func (b *Buffer) WriteRune(r rune) (n int, err error) {
 }
 
 // Read reads the next len(p) bytes from the buffer or until the buffer
-// is drained.  The return value n is the number of bytes read.  If the
+// is drained. The return value n is the number of bytes read. If the
 // buffer has no data to return, err is io.EOF (unless len(p) is zero);
 // otherwise it is nil.
 func (b *Buffer) Read(p []byte) (n int, err error) {
@@ -347,7 +347,7 @@ func (b *Buffer) UnreadRune() error {
 }
 
 // UnreadByte unreads the last byte returned by the most recent
-// read operation.  If write has happened since the last read, UnreadByte
+// read operation. If write has happened since the last read, UnreadByte
 // returns an error.
 func (b *Buffer) UnreadByte() error {
 	if b.lastRead != opReadRune && b.lastRead != opRead {
@@ -400,7 +400,7 @@ func (b *Buffer) ReadString(delim byte) (line string, err error) {
 }
 
 // NewBuffer creates and initializes a new Buffer using buf as its initial
-// contents.  It is intended to prepare a Buffer to read existing data.  It
+// contents. It is intended to prepare a Buffer to read existing data. It
 // can also be used to size the internal buffer for writing. To do that,
 // buf should have the desired capacity but a length of zero.
 //