exercises/practice/anagram: add an append with instructions about the order of the return values (#2848)

Author: IsaacG

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

@@ -1,4 +1,6 @@
 # Implementation
 
+You must return the anagrams in the same order as they are listed in the candidate words.
+
 Unlike other tracks, the Go version of the exercise includes test cases that use UTF-8 (non-ASCII) characters in the strings.
-However, with Go's first-class support for UTF-8 given by the `rune` type, that should not bother you too much.
+However, with Go's first-class support for UTF-8 given by the `rune` type, that should not bother you too much.