Translated `documentation/performance/index.html`
补翻译一处
Fixed typo
ryan branch

Signed-off-by: ryanyr <335023379@qq.com>
Merge branch 'master' of git@github.com:ryanyr/google-web-fundamentals-simplified-chinese.git

Conflicts:
	documentation/introduction-to-media/images/index.html
	documentation/multi-device-layouts/index.html
	documentation/performance/index-2.html
	documentation/performance/index.html
	getting-started/your-first-multi-screen-site/index.html
	index.html
	resources/index.html
	resources/samples/index.html

Signed-off-by: ryanyr <335023379@qq.com>
Signed-off-by: ryanyr <335023379@qq.com>
Merge pull request #8 from ryanyr/master

doufu's complete page
`
orig
Merge pull request #7 from xavieryao/master

Translated `documentation/performance/index.html`
Merge pull request #2 from lostlandark/master

merge upstream