Fix: Distinguish between DeclareFunction and FunctionDeclaration (refs #78)

[JamesHenry]

No description provided.

[eslintbot]

Thanks for the pull request, @JamesHenry! I took a look to make sure it's ready for merging and found some changes are needed:

• Pull requests with code require an issue to be mentioned at the end of the commit summary, such as (fixes #1234). Please update the commit summary with an issue (file a new issue if one doesn't already exist).

Can you please update the pull request to address these?

(More information can be found in our pull request guide.)

[nzakas]

Lgtm