Reverse function. Closes #94.

docs/content/3.manual/manual.yml

@@ -718,6 +718,16 @@ sections:
             input: '[1,2,5,3,5,3,1,3]'
             output: ['[1,2,3,5]']
 
+      - title: `reverse`
+        body: |
+          
+          This function reverses an array.
+
+        examples:
+          - program: 'reverse'
+            input: '[1,2,3,4]'
+            output: ['[4,3,2,1]']
+
       - title: `contains`
         body: |