In CompileAtom, copy wording-changes

... prompted by tc39#2418 (comment)
from `Atom :: CharacterClass` semantics
to `AtomEscape :: CharacterClassEscape` semantics.

spec.html

@@ -36445,17 +36445,17 @@ <h1>
         <emu-grammar>AtomEscape :: CharacterClassEscape</emu-grammar>
         <emu-alg>
           1. Let _cs_ be CompileToCharSet of |CharacterClassEscape| with argument _rer_.
-          1. If _rer_.[[UnicodeSets]] is *false*, or if every element of _cs_ consists of a single character (including if _cs_ is empty), return CharacterSetMatcher(_rer_, _cs_, *false*, _direction_).
+          1. If _rer_.[[UnicodeSets]] is *false*, or if every CharSetElement of _cs_ consists of a single character (including if _cs_ is empty), return CharacterSetMatcher(_rer_, _cs_, *false*, _direction_).
           1. Let _lm_ be an empty List of Matchers.
-          1. For each string _s_ in _cs_ whose length is greater than 1, iterating in descending order of string length, do
+          1. For each CharSetElement _s_ in _cs_ containing more than 1 character, iterating in descending order of length, do
             1. Let _cs2_ be a one-element CharSet containing the last code point of _s_.
             1. Let _m2_ be CharacterSetMatcher(_rer_, _cs2_, *false*, _direction_).
             1. For each code point _c1_ in _s_, iterating backwards from its second-to-last code point, do
               1. Let _cs1_ be a one-element CharSet containing _c1_.
               1. Let _m1_ be CharacterSetMatcher(_rer_, _cs1_, *false*, _direction_).
               1. Set _m2_ to MatchSequence(_m1_, _m2_, _direction_).
             1. Append _m2_ to _lm_.
-          1. Let _singles_ be the CharSet containing every element of _cs_ which consists of a single character.
+          1. Let _singles_ be the CharSet containing every CharSetElement of _cs_ which consists of a single character.
           1. Append CharacterSetMatcher(_rer_, _singles_, *false*, _direction_) to _lm_.
           1. If _cs_ contains the empty sequence of characters, append EmptyMatcher() to _lm_.
           1. Let _m2_ be the last Matcher in _lm_.