Normalize the method listings

[javiereguiluz]

When listing a lot of related methods, documentation pages use different strategies:

1) Regular <ul> lists (see http://symfony.com/doc/current/components/http_foundation/sessions.html#session-api)

2) Regular <dl> lists (see http://symfony.com/doc/current/components/config/definition.html#default-and-required-values)

3) Weird mix of <ul> and <dl> lists

Is it worth it to normalize these method listings?

[wouterj]

Yes, it is worth normalizing. Consistency is an important part of good docs imo.

I'm +1 for the definition list variant, I didn't knew it existed before this issue :)

[weaverryan]

Yep, I like the dl one too. I like consistency, but I like even more using what looks best in the most places.

[xabbuh]

I agree with you that the definition lists look the best.

[xabbuh]

We should also merge #4550.