purescript-font-lock.el: assume purescript-literate is always bound

Now that it's exported from a common location, there's no reason it
shouldn't be (besides a bug of course).

Author: Hi-Angel

purescript-font-lock.el

@@ -306,13 +306,13 @@ Returns keywords suitable for `font-lock-keywords'."
 
 ;;;###autoload
 (defun purescript-font-lock-choose-keywords ()
-  (cl-case (bound-and-true-p purescript-literate)
+  (cl-case purescript-literate
     (bird purescript-font-lock-bird-literate-keywords)
     ((latex tex) purescript-font-lock-latex-literate-keywords)
     (t purescript-font-lock-keywords)))
 
 (defun purescript-font-lock-choose-syntactic-keywords ()
-  (cl-case (bound-and-true-p purescript-literate)
+  (cl-case purescript-literate
     (bird purescript-bird-syntactic-keywords)
     ((latex tex) purescript-latex-syntactic-keywords)
     (t purescript-basic-syntactic-keywords)))