Editorial: Simplify the 'Atom' production

... by merging the two capturing-group alternatives.

(This may be affected by the outcome of issue tc39#1673.)

spec.html

@@ -33947,8 +33947,7 @@ <h2>Patterns</h2>
           `\` AtomEscape[?UnicodeMode, ?N]
           [~UnicodeMode] `\` [lookahead == `c`]
           CharacterClass[?UnicodeMode]
-          [+UnicodeMode] `(` GroupSpecifier[?UnicodeMode] Disjunction[?UnicodeMode, ?N] `)`
-          [~UnicodeMode] `(` Disjunction[?UnicodeMode, ?N] `)`
+          `(` GroupSpecifier[?UnicodeMode] Disjunction[?UnicodeMode, ?N] `)`
           `(` `?` `:` Disjunction[?UnicodeMode, ?N] `)`
           [~UnicodeMode] InvalidBracedQuantifier
           [+UnicodeMode] PatternCharacter
@@ -33973,7 +33972,7 @@ <h2>Group Specifiers</h2>
       <emu-grammar type="definition">
         GroupSpecifier[UnicodeMode] ::
           [empty]
-          `?` GroupName[?UnicodeMode]
+          [+UnicodeMode] `?` GroupName[?UnicodeMode]
 
         GroupName[UnicodeMode] ::
           `&lt;` RegExpIdentifierName[?UnicodeMode] `&gt;`
@@ -34698,8 +34697,6 @@ <h1>Term</h1>
             1. Assert: _c_ is a Continuation.
             1. Return ! RepeatMatcher(_m_, _min_, _max_, _greedy_, _x_, _c_, _parenIndex_, _parenCount_).
         </emu-alg>
-        <p>----</p>
-        <p>In the above algorithm, references to <emu-grammar>Atom ::! `(` GroupSpecifier Disjunction `)`</emu-grammar> are to be interpreted as meaning <emu-grammar>Atom ::! `(` GroupSpecifier Disjunction `)`</emu-grammar> or <emu-grammar>Atom ::! `(` Disjunction `)`</emu-grammar> .</p>
         <p>The production <emu-grammar>Term ::! QuantifiableAssertion Quantifier</emu-grammar> evaluates the same as the production <emu-grammar>Term ::! Atom Quantifier</emu-grammar> but with |QuantifiableAssertion| substituted for |Atom|.</p>
 
         <emu-clause id="sec-runtime-semantics-repeatmatcher-abstract-operation" type="abstract operation">