Clean up some typos in GN quick start page.

Clean up some typos in GN quick start page.

Also adjust the sample code a bit.

BUG=none

Committed: https://crrev.com/19c81c689ac484b960dcbfb8633e1723245e5810
Cr-Commit-Position: refs/heads/master@{#341213}

[Bons, 2015-07-30 22:10:16]

andybons@chromium.org changed reviewers:
+ dpranke@chromium.org

[Bons, 2015-07-30 22:10:16]

andybons@chromium.org changed required reviewers:
+ dpranke@chromium.org

[Bons, 2015-07-30 22:19:05]

andybons@chromium.org changed reviewers:
+ brettw@chromium.org

[Bons, 2015-07-30 22:19:05]

andybons@chromium.org changed required reviewers:
+ brettw@chromium.org
- dpranke@chromium.org

[Bons, 2015-07-30 22:19:05]

+brettw

[Dirk Pranke, 2015-07-30 22:26:23]

lgtm

[Dirk Pranke, 2015-07-30 22:26:34]

dpranke@chromium.org changed required reviewers:
- brettw@chromium.org

[Bons, 2015-07-30 22:26:38]

The CQ bit was checked by andybons@chromium.org

[commit-bot: I haz the power, 2015-07-30 22:27:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1259763004/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1259763004/20001

[commit-bot: I haz the power, 2015-07-30 22:38:11]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-07-30 22:38:56]

Patchset 2 (id:??) landed as
https://crrev.com/19c81c689ac484b960dcbfb8633e1723245e5810
Cr-Commit-Position: refs/heads/master@{#341213}

[Nico, 2015-07-30 22:42:51]

thakis@chromium.org changed reviewers:
+ thakis@chromium.org

[Nico, 2015-07-30 22:42:51]

https://codereview.chromium.org/1259763004/diff/20001/tools/gn/tutorial/say_h...
File tools/gn/tutorial/say_hello.cc (right):

https://codereview.chromium.org/1259763004/diff/20001/tools/gn/tutorial/say_h...
tools/gn/tutorial/say_hello.cc:9: Hello("Bill", "Joy");
lgtm++