fix #64 - formatting

Author: PhilippSalvisberg

docs/4-language-usage/4-control-structures/2-case-if-decode-nvl-nvl2-coalesce/g-4220.md

@@ -11,9 +11,9 @@
 
 ```
 SELECT DECODE(dummy, 'X', 1 
-                      , 'Y', 2
-                      , 'Z', 3
-                      , 0)
+                   , 'Y', 2
+                   , 'Z', 3
+                        , 0)
   FROM dual;
 ```