Update simplification.md

The argument was wrong in my example tests!

site/2022/simplification.md

@@ -40,7 +40,7 @@ class ConversionTest < Minitest::Test
       This is a paragraph
     EXPECTED
 
-    actual = Conversion.new(expected).output
+    actual = Conversion.new(input).output
     assert_equal expected, actual, "conversion should work"
 
     actual = Conversion.new(actual).output
@@ -234,4 +234,4 @@ I have my problems.
 I want the minimal tool that solves my problems.
 I want to build that tool to better understand my problems.
 And grow.
-It's for fun.
+It's for fun.