Editorial: Fix Annex B step number reference (#1636)

Commit ea16790 inserted a step,
pushing the Annex B 'insertion point'
from step 28 to step 29.

spec.html

@@ -41142,7 +41142,7 @@ <h1>Block-Level Function Declarations Web Legacy Compatibility Semantics</h1>
       <p>If an ECMAScript implementation has a mechanism for reporting diagnostic warning messages, a warning should be produced when code contains a |FunctionDeclaration| for which these compatibility semantics are applied and introduce observable differences from non-compatibility semantics. For example, if a var binding is not introduced because its introduction would create an early error, a warning message should not be produced.</p>
       <emu-annex id="sec-web-compat-functiondeclarationinstantiation">
         <h1>Changes to FunctionDeclarationInstantiation</h1>
-        <p>During FunctionDeclarationInstantiation the following steps are performed in place of step 28:</p>
+        <p>During FunctionDeclarationInstantiation the following steps are performed in place of step 29:</p>
         <emu-alg>
           1. If _strict_ is *false*, then
             1. For each |FunctionDeclaration| _f_ that is directly contained in the |StatementList| of a |Block|, |CaseClause|, or |DefaultClause|, do