Fix support of Clojure framework Hoplon

An attempt to add support for the Clojure framework Hoplon was made in #854. Except Linguist doesn't support file extension with multiple segments (see #1388).
I removed the two lines and added support only for `.hl` in Clojure (strangely the classifier Bayesian wasn't able to distinguish `.cljs.hl` and `.html.hl` files).
It means that for the time being (and until we can add some heuristics on this), every `.hl` files will be recognized as Clojure. I made a few searches and there seems to be few `.html.hl` compared to the `.cljs.hl` on GitHub. Thus, I think it still improves the situation (since `.hl` aren't recognized at all currently).