regexp: add QuoteMeta example

Change-Id: I0bbb53cad9a7c464ab1cfca381128f33496813ff
Reviewed-on: https://go-review.googlesource.com/49130Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/regexp/example_test.go

@@ -38,6 +38,12 @@ func ExampleMatchString() {
 	// false error parsing regexp: missing closing ): `a(b`
 }
 
+func ExampleQuoteMeta() {
+	fmt.Println(regexp.QuoteMeta("Escaping symbols like: .+*?()|[]{}^$"))
+	// Output:
+	// Escaping symbols like: \.\+\*\?\(\)\|\[\]\{\}\^\$
+}
+
 func ExampleRegexp_FindString() {
 	re := regexp.MustCompile("foo.?")
 	fmt.Printf("%q\n", re.FindString("seafood fool"))

src/regexp/regexp.go

@@ -616,9 +616,9 @@ func init() {
 	}
 }
 
-// QuoteMeta returns a string that quotes all regular expression metacharacters
+// QuoteMeta returns a string that escapes all regular expression metacharacters
 // inside the argument text; the returned string is a regular expression matching
-// the literal text. For example, QuoteMeta(`[foo]`) returns `\[foo\]`.
+// the literal text.
 func QuoteMeta(s string) string {
 	// A byte loop is correct because all metacharacters are ASCII.
 	var i int