Update docs for new Sdump function.

spew/config.go

@@ -242,7 +242,8 @@ package:
 The configuration options are controlled by modifying the public members
 of c.  See ConfigState for options documentation.
 
-See Fdump if you would prefer dumping to an arbitrary io.Writer.
+See Fdump if you would prefer dumping to an arbitrary io.Writer or Sdump to
+get the formatted result as a string.
 */
 func (c *ConfigState) Dump(a ...interface{}) {
 	fdump(c, os.Stdout, a...)

spew/doc.go

@@ -49,9 +49,10 @@ This section demonstrates how to quickly get started with spew.  See the
 sections below for further details on formatting and configuration options.
 
 To dump a variable with full newlines, indentation, type, and pointer
-information use Dump or Fdump:
+information use Dump, Fdump, or Sdump:
 	spew.Dump(myVar1, myVar2, ...)
 	spew.Fdump(someWriter, myVar1, myVar2, ...)
+	str := spew.Sdump(myVar1, myVar2, ...)
 
 Alternatively, if you would prefer to use format strings with a compacted inline
 printing style, use the convenience wrappers Printf, Fprintf, etc with
@@ -105,6 +106,10 @@ io.Writer.  For example, to dump to standard error:
 
 	spew.Fdump(os.Stderr, myVar1, myVar2, ...)
 
+A third option is to call spew.Sdump to get the formatted output as a string:
+
+	str := spew.Sdump(myVar1, myVar2, ...)
+
 Sample Dump Output
 
 See the Dump example for details on the setup of the types and variables being

spew/dump.go

@@ -391,7 +391,8 @@ package:
 The configuration options are controlled by an exported package global,
 spew.Config.  See ConfigState for options documentation.
 
-See Fdump if you would prefer dumping to an arbitrary io.Writer.
+See Fdump if you would prefer dumping to an arbitrary io.Writer or Sdump to
+get the formatted result as a string.
 */
 func Dump(a ...interface{}) {
 	fdump(&Config, os.Stdout, a...)