Suppress new clang-tidy checks

    $ clang-tidy-18 src/cxx.cc --warnings-as-errors=*
    2482 warnings generated.
    /git/cxx/src/cxx.cc:205:10: error: avoid repeating the return type from the declaration; use a braced initializer list instead [modernize-return-braced-init-list,-warnings-as-errors]
      205 |   return std::string(this->data(), this->size());
          |          ^
    /git/cxx/src/cxx.cc:318:10: error: avoid repeating the return type from the declaration; use a braced initializer list instead [modernize-return-braced-init-list,-warnings-as-errors]
      318 |   return std::string(this->data(), this->size());
          |          ^
    /git/cxx/src/cxx.cc:542:17: error: member 'throw$' of type 'repr::PtrLen &' is a reference [cppcoreguidelines-avoid-const-or-ref-data-members,-warnings-as-errors]
      542 |   repr::PtrLen &throw$;
          |                 ^
    Suppressed 2479 warnings (2479 in non-user code).
    Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
    3 warnings treated as errors

.clang-tidy

@@ -3,6 +3,7 @@ Checks:
   clang-diagnostic-*,
   cppcoreguidelines-*,
   modernize-*,
+  -cppcoreguidelines-avoid-const-or-ref-data-members,
   -cppcoreguidelines-macro-usage,
   -cppcoreguidelines-owning-memory,
   -cppcoreguidelines-pro-bounds-array-to-pointer-decay,
@@ -12,6 +13,7 @@ Checks:
   -cppcoreguidelines-pro-type-reinterpret-cast,
   -cppcoreguidelines-pro-type-vararg,
   -cppcoreguidelines-special-member-functions,
+  -modernize-return-braced-init-list,
   -modernize-use-default-member-init,
   -modernize-use-equals-default,
   -modernize-use-trailing-return-type,