FAQ.rst:Replace a FAQ

[sarthakchakerverty]

Replace a FAQ about pull requests with how to contribute to coala.

closes: #552

For short term contributors: we understand that getting your commits well
defined like we require is a hard task and takes some learning. If you
look to help without wanting to contribute long term there's no need
for you to learn this. Just drop us a message and we'll take care of brushing
up your stuff for merge!

Checklist

• I read the commit guidelines and I've followed
  them.
• I ran coala over my code locally. (All commits have to pass
  individually. It is not sufficient to have "fixup commits" on your PR,
  our bot will still report the issues for the previous commit.) You will
  likely receive a lot of bot comments and build failures if coala does not
  pass on every single commit!

After you submit your pull request, DO NOT click the 'Update Branch' button.
When asked for a rebase, consult coala.io/rebase
instead.

Please consider helping us by reviewing other peoples pull requests as well:

• pick up any PR at https://coala.io/review
• review it (check https://coala.io/reviewing for more info)
• if you are sure that it needs work, use corobo mark wip <URL> to get it out
  of the review queue.

The more you review, the more your score will grow at coala.io and we will
review your PRs faster!

[chhabrabhishek]

The question must be in heading format.
And you can work on your code syntax correction of the code for RST format.
To check syntax please refer "http://www.sphinx-doc.org/en/master/usage/restructuredtext/basics.html".
Also, improve your commit message by correcting the typo from reaplace->replace.

[sarthakchakerverty]

@chhabrabhishek made the requested changes.

[jayvdb]

There are three commits at https://github.com/coala/documentation/pull/566/commits

Please squash your commits

[sarthakchakerverty]

@chhabrabhishek @jayvdb squashed the commits.Please review!

[jayvdb]

Looking better.

Now amend your commit message to be exactly as described at https://coala.io/commit .

It is checked by a bot. Your patch will keep being rejected until you follow it precisely.

[sarthakchakerverty]

@jayvdb Commit message is now editted.

[jayvdb]

At least two things wrong with your commit message.

[utkarsh2102]

Please change the commit message as per the commit guidelines.
Send a fix at the earliest.

[ManthanKeim]

There's a missing space in your commit message.