Update assetic watch command

[geerteltink]

Q	A
Doc fix?	yes
New docs?	no
Applies to	2.6
Fixed tickets	-

I'm getting this message:

The --watch option is deprecated. Please use the assetic:watch command instead.

[javiereguiluz]

@xtreamwayz thanks for updating this command!

When Symfony changes a well-known feature, option or command, we usually add a message in the newer version of the docs to help experienced Symfony developers realize that things have changed. In this case, we could add something like the following:

.. versionadded:: 2.6
    Prior to Symfony 2.6 the ``assetic:watch`` command was executed via the
    ``--watch`` option of the ``assecit:dump`` command.

In any case, let's see what do our code reviewers (@wouterj and @xabbuh) think about this idea.

[xabbuh]

@xtreamwayz Good catch and very valuable change.

As @javiereguiluz said, you simply have to add the versionadded directive. According to the doc standards, it should be worded like:

.. versionadded:: 2.6
    The ``assetic:watch`` command was introduced in Symfony 2.6. In prior
    versions, you had to use the ``--watch`` option of the ``assetic:dump``
    command for the same behavior.

[stof]

This is not related to Symfony 2.6. It is related to AsseticBundle 2.4, which is compatible with Symfony 2.1+

[geerteltink]

Updated the text. Not sure if this is better. If not, feel free to adjust.

[wouterj]

I like it (and sorry for missing this PR). I've tagged it with finished, so the merger will see that this PR is mergable.

Note for @weaverryan, this should be merged into the 2.3 branch.

[xabbuh]

@xtreamwayz Sorry for not coming back to you after you applied the changes. I like the way you worded the sentence. 👍

[weaverryan]

Nice job guys, with the versionadded on the AsseticBundle version, I think it's the only way. I am merging this into 2.3, though there is some risk - the VAST majority of 2.3 projects will likely use the older AsseticBundle version. But, I think it'll be a really thing to be able to find and fix. Anyways, thanks @xtreamwayz!