Editorial: Change "Step 2.a" to "Step 2.b" in RepeatMatcher note

PR tc39#1889 (among other things) inserted a step before the former 2.a,
but didn't update the note that referenced it.

spec.html

@@ -31541,7 +31541,7 @@ <h1>Runtime Semantics: RepeatMatcher ( _m_, _min_, _max_, _greedy_, _x_, _c_, _p
             <p>because each iteration of the outermost `*` clears all captured Strings contained in the quantified |Atom|, which in this case includes capture Strings numbered 2, 3, 4, and 5.</p>
           </emu-note>
           <emu-note>
-            <p>Step 2.a of the RepeatMatcher states that once the minimum number of repetitions has been satisfied, any more expansions of |Atom| that match the empty character sequence are not considered for further repetitions. This prevents the regular expression engine from falling into an infinite loop on patterns such as:</p>
+            <p>Step 2.b of the RepeatMatcher states that once the minimum number of repetitions has been satisfied, any more expansions of |Atom| that match the empty character sequence are not considered for further repetitions. This prevents the regular expression engine from falling into an infinite loop on patterns such as:</p>
             <pre><code class="javascript">/(a*)*/.exec("b")</code></pre>
             <p>or the slightly more complicated:</p>
             <pre><code class="javascript">/(a*)b\1+/.exec("baaaac")</code></pre>