pig-latin: update docs (#2149)

[no important files changed]

exercises/practice/pig-latin/.docs/instructions.md

@@ -8,11 +8,12 @@ It obeys a few simple rules (below), but when it's spoken quickly it's really di
 - **Rule 1**: If a word begins with a vowel sound, add an "ay" sound to the end of the word.
   Please note that "xr" and "yt" at the beginning of a word make vowel sounds (e.g. "xray" -> "xrayay", "yttria" -> "yttriaay").
 - **Rule 2**: If a word begins with a consonant sound, move it to the end of the word and then add an "ay" sound to the end of the word.
-  Consonant sounds can be made up of multiple consonants, a.k.a. a consonant cluster (e.g. "chair" -> "airchay").
+  Consonant sounds can be made up of multiple consonants, such as the "ch" in "chair" or "st" in "stand" (e.g. "chair" -> "airchay").
 - **Rule 3**: If a word starts with a consonant sound followed by "qu", move it to the end of the word, and then add an "ay" sound to the end of the word (e.g. "square" -> "aresquay").
 - **Rule 4**: If a word contains a "y" after a consonant cluster or as the second letter in a two letter word it makes a vowel sound (e.g. "rhythm" -> "ythmrhay", "my" -> "ymay").
 
 There are a few more rules for edge cases, and there are regional variants too.
+Check the tests for all the details.
 
 Read more about [Pig Latin on Wikipedia][pig-latin].