Introduce declarations to haskell-yas.el so it byte-compiles cleanly.

[Fanael]

Without them:

In haskell-snippets-initialize:
haskell-yas.el:60:17:Warning: reference to free variable `yas-snippet-dirs'
haskell-yas.el:61:23:Warning: assignment to free variable `yas-snippet-dirs'

In end of data:
haskell-yas.el:73:1:Warning: the function `yas-load-directory' is not known to
    be defined.

[purcell]

I understand the motivation, but do you think this is worthwhile? I personally don't mind seeing these particular warnings because they're a reminder that there's a missing package dependency. haskell-yas should really be a separate package.

[Fanael]

Oh, okay then.

[Fanael]

I mean, as a user I like to see packages compile cleanly[1], but it seems there's a good reason in this case.

1. Unlike say smartparens, where byte compilation reveals some real bugs.

[purcell]

Unlike say smartparens

Yup!