Fix operator with no arguments lint incorrect report.

Operator with no arguments check failed when the first argument to the
operator was falsy. We might want to have a new lint to check for
"always false/true" expressions but this report was incorrect and the
quickfix replaced incorrect code.

src/fennel-ls/lint.fnl

@@ -181,7 +181,7 @@ the `file.diagnostics` field, filling it with diagnostics."
   "A call like (+) that could be replaced with a literal"
   (let [identity (. op-identity-value (tostring op))]
     (if (and (op? op)
-             (not (. call 2))
+             (= 1 (length call))
              (. file.lexical call)
              (not= nil identity))
       (diagnostic

test/lint.fnl

@@ -252,6 +252,17 @@
                    :end {:character 6 :line 0}}}])
   nil)
 
+(fn test-op-with-no-arguments []
+  (assert-ok "(and 1)")
+  (assert-ok "(and false 1)")
+  (assert-ok "(and nil 1)")
+  (check "(and)"
+         {:message "write true instead of (and)"
+          :code :op-with-no-arguments
+          :range {:start {:characer 0 :line 0}
+                  :end {:character 5 :line 0}}})
+  nil)
+
 ;; TODO lints:
 ;; duplicate keys in kv table
 ;; (tset <sym> <any>) --> (set (. <sym> <any>)) (might be wanted for compat?)
@@ -274,5 +285,5 @@
  : test-unset-var
  : test-match-should-case
  : test-unpack-into-op
- : test-unpack-in-middle}
- 
+ : test-unpack-in-middle
+ : test-op-with-no-arguments}