Some IllegalArgumentException messages in `error_dictionary.clj` incorrectly assume that a sequence was passed

[stanislowskij]

Certain functions that expect an integer argument and are not spec'd by Babel get caught by the :illegal-arg-must-be-int-seq error in our error_dictionary.clj. The message for this is misleading in cases where a sequence is not passed.

To reproduce/test:

1. Since (even?) and (odd?) are currently underspec'd, passing a double to them instead of an int will produce these errors:

babel.middleware=> (odd? 2.4)

Expected an integer number, but a sequence 2.4 was given instead.

2. Entirely removing the spec for these functions also produces the same error for any non-integer argument.

Using a spec'd predicate in a higher-level spec seemingly "bypasses" the specs on the predicate function due to being evaluated differently from user code. This is also an unavoidable case, i.e. a cause for why these messages need to be improved even if the specs are fixed:

In corefns.clj:

(s/fdef clojure.core/even?
  :args :babel.args/one-number)
(stest/instrument `clojure.core/even?)
(defn x [n] n)
(s/fdef x :args (s/cat :number even?))
(stest/instrument `x)

babel.middleware=> (corefns.corefns/x :a)

Expected an integer number, but a sequence :a was given instead.

TODO: Find examples of the other one:

{:key :illegal-arg-must-be-int-lazy
    :class "IllegalArgumentException"
    :match (beginandend #"Argument must be an integer: clojure\.lang\.LazySeq(.*)")
    :fn (fn [matches] (str "Expected an integer number, but a sequence was given instead.\n"))}