[lldb][DWARFASTParserClang][NFC] Clarify comment around static member variable handling (#72495)

Author: Michael137

lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp

@@ -2963,9 +2963,9 @@ void DWARFASTParserClang::ParseSingleMember(
   // whereas GCC emits it only for static data members if not part of an
   // anonymous namespace. The flag that is consistently emitted for static
   // data members is DW_AT_declaration, so we check it instead.
-  // FIXME: Since DWARFv5, static data members are marked DW_AT_variable so we
+  // The following block is only necessary to support DWARFv4 and earlier.
+  // Starting with DWARFv5, static data members are marked DW_AT_variable so we
   // can consistently detect them on both GCC and Clang without below heuristic.
-  // Remove this block if we ever drop DWARFv4 support.
   if (attrs.member_byte_offset == UINT32_MAX &&
       attrs.data_bit_offset == UINT64_MAX && attrs.is_declaration) {
     CreateStaticMemberVariable(die, attrs, class_clang_type);