Add describe and test to the list of keywords

[rakr]

Added describe and test to the list of keywords in order to differentiate them when using syntax highlighting.

[timmhirsens]

I must admit, i am not really good at regexes. But to clarify, would this match something like this:

def test do
  {:ok. nil}
end

?

[rakr]

This would highlight the keyword describe and test in the test files differently

describe "homepage" do
  test "it displays the latest information on the homepage", %{conn: _conn} do
    ...
  end
end

[woolfred]

While it won't interfere with highlighting the function signature correctly, it highlights the use of a self defined test function

But I would also like to see highlighting for test and describe!