exercises/practice/anagram: add an append with instructions about the order of the return values

Author: IsaacG

exercises/practice/anagram/.docs/instructions.append.md

@@ -4,6 +4,8 @@
 
 Each set of words is represented as a null-terminated string, with a newline character at the end of each word.
 
+You must return the anagrams in the same order as they are listed in the candidate words.
+
 An example would be `"tones\nnotes\nSeton\n"`
 
 ## Registers