Adjust blanks to be the same length

This way, the test framework can throw the correct errors for these
tests as it only allows blanks of exactly four underscores.

koans/functions.lisp

@@ -122,8 +122,8 @@
     (assert-equal ____ (funcall (fourth functions) 2 33))))
 
 (define-test lambda-with-optional-parameters
-  (assert-equal ___ ((lambda (a &optional (b 100)) (+ a b)) 10 9))
-  (assert-equal ___ ((lambda (a &optional (b 100)) (+ a b)) 10)))
+  (assert-equal ____ ((lambda (a &optional (b 100)) (+ a b)) 10 9))
+  (assert-equal ____ ((lambda (a &optional (b 100)) (+ a b)) 10)))
 
 (defun make-adder (x)
   ;; MAKE-ADDER will create a function that closes over the parameter X.

koans/strings.lisp

@@ -26,7 +26,7 @@
   (let ((string "this is
                  a multi
                  line string"))
-    (true-or-false? ___ (typep string 'string))))
+    (true-or-false? ____ (typep string 'string))))
 
 (define-test escapes-in-strings
   ;; Quotes and backslashes in Lisp strings must be escaped.