net: fix protocol number for IPv6 test

The protocol number of ICMP for IPv6 is 58, not 1.

R=golang-dev, iant, r
CC=golang-dev
https://codereview.appspot.com/8663048
doc/effective_go.html: fix syntax error in code example
Fixes issue 5333.

R=golang-dev, adg
CC=golang-dev
https://codereview.appspot.com/8698046
doc: fix typo in race_detector.html

R=golang-dev, bradfitz
CC=golang-dev
https://codereview.appspot.com/8625044

Committer: Brad Fitzpatrick <bradfitz@golang.org>
doc/code.html: remove doubled word; modify the tab to space.

R=golang-dev, bradfitz
CC=golang-dev
https://codereview.appspot.com/8919043

Committer: Brad Fitzpatrick <bradfitz@golang.org>
all: fix typos

R=golang-dev, bradfitz
CC=golang-dev
https://codereview.appspot.com/8896045
cmd/dist: fix line numbers in goc2c generated files

We have to reset the global lineno variable before
processing each file otherwise line numbers will be
offset by the number of lines in the previous file.

The following examples are from the beginning of the
ztime_linux_amd64.c file which is generated from
time.goc in the runtime package.

Before:
    #line 2483 "/home/apm/src/go/src/pkg/runtime/time.goc"
    static Timers timers;
    static void addtimer ( Timer* ) ;
    void
    time·Sleep(int64 ns)
    {
    #line 2492 "/home/apm/src/go/src/pkg/runtime/time.goc"

After:
    #line 16 "/home/apm/src/go/src/pkg/runtime/time.goc"
    static Timers timers;
    static void addtimer ( Timer* ) ;
    void
    time·Sleep(int64 ns)
    {
    #line 25 "/home/apm/src/go/src/pkg/runtime/time.goc"

R=golang-dev, minux.ma, iant, r, adg
CC=golang-dev
https://codereview.appspot.com/8653045
net: add missing File method document

R=golang-dev, bradfitz, r
CC=golang-dev
https://codereview.appspot.com/8698049