bison: port to GCC 16.1.1 -Wmaybe-uninitialized

* data/skeletons/lalr1.cc: Increase the scope of
YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN.
Needed for GCC 16.1.1 20260515 (Red Hat 16.1.1-2).

data/skeletons/lalr1.cc

@@ -843,6 +843,7 @@ m4_if(b4_prefix, [yy], [],
   int
   ]b4_parser_class[::parse ()
   {
+    YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
     int yyn;
     /// Length of the RHS of the rule being reduced.
     int yylen = 0;
@@ -987,7 +988,6 @@ b4_dollar_popdef])[]dnl
   yyreduce:
     yylen = yyr2_[yyn];
     {
-      YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
       stack_symbol_type yylhs;
       yylhs.state = yy_lr_goto_state_ (yystack_[yylen].state, yyr1_[yyn]);]b4_variant_if([[
       /* Variants are always initialized to an empty instance of the
@@ -1040,7 +1040,6 @@ b4_dollar_popdef])[]dnl
 
       // Shift the result of the reduction.
       yypush_ (YY_NULLPTR, YY_MOVE (yylhs));
-      YY_IGNORE_MAYBE_UNINITIALIZED_END
     }
     goto yynewstate;
 
@@ -1181,6 +1180,7 @@ b4_dollar_popdef])[]dnl
       }
 
     return yyresult;
+    YY_IGNORE_MAYBE_UNINITIALIZED_END
   }
 #if YY_EXCEPTIONS
     catch (...)