net/http/httputil: fix typos in deprecation comments

Fixes #15868

Change-Id: I4e4471e77091309c4ea1d546b2c4f20dfbb4314e
Reviewed-on: https://go-review.googlesource.com/23550Reviewed-by: Andrew Gerrand <adg@golang.org>

src/net/http/httputil/persist.go

@@ -25,7 +25,7 @@ var (
 var errClosed = errors.New("i/o operation on closed connection")
 
 // ServerConn is an artifact of Go's early HTTP implementation.
-// Is is low-level, old, and unused by Go's current HTTP stack.
+// It is low-level, old, and unused by Go's current HTTP stack.
 // We should have deleted it before Go 1.
 //
 // Deprecated: Use the Server in package net/http instead.
@@ -42,7 +42,7 @@ type ServerConn struct {
 }
 
 // NewServerConn is an artifact of Go's early HTTP implementation.
-// Is is low-level, old, and unused by Go's current HTTP stack.
+// It is low-level, old, and unused by Go's current HTTP stack.
 // We should have deleted it before Go 1.
 //
 // Deprecated: Use the Server in package net/http instead.
@@ -218,7 +218,7 @@ func (sc *ServerConn) Write(req *http.Request, resp *http.Response) error {
 }
 
 // ClientConn is an artifact of Go's early HTTP implementation.
-// Is is low-level, old, and unused by Go's current HTTP stack.
+// It is low-level, old, and unused by Go's current HTTP stack.
 // We should have deleted it before Go 1.
 //
 // Deprecated: Use Client or Transport in package net/http instead.
@@ -236,7 +236,7 @@ type ClientConn struct {
 }
 
 // NewClientConn is an artifact of Go's early HTTP implementation.
-// Is is low-level, old, and unused by Go's current HTTP stack.
+// It is low-level, old, and unused by Go's current HTTP stack.
 // We should have deleted it before Go 1.
 //
 // Deprecated: Use the Client or Transport in package net/http instead.
@@ -253,7 +253,7 @@ func NewClientConn(c net.Conn, r *bufio.Reader) *ClientConn {
 }
 
 // NewProxyClientConn is an artifact of Go's early HTTP implementation.
-// Is is low-level, old, and unused by Go's current HTTP stack.
+// It is low-level, old, and unused by Go's current HTTP stack.
 // We should have deleted it before Go 1.
 //
 // Deprecated: Use the Client or Transport in package net/http instead.