[wasm-gc] Remove obsolete TODO comments

Bug: v8:7748
Change-Id: Icde19a554042ce57420a1faa72492c53a07dbc66
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3905723
Auto-Submit: Matthias Liedtke <mliedtke@chromium.org>
Reviewed-by: Manos Koukoutos <manoskouk@chromium.org>
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#83336}

src/wasm/module-decoder-impl.h

@@ -2357,7 +2357,9 @@ class ModuleDecoderTemplate : public Decoder {
       } else {
         type = table_type;
         // Active segments with function indices must reference a function
-        // table. TODO(7748): Add support for anyref tables when we have them.
+        // table. (Using struct / array indices doesn't provide any value
+        // as such an index doesn't refer to a unique object instance unlike
+        // functions.)
         if (V8_UNLIKELY(
                 !IsSubtypeOf(table_type, kWasmFuncRef, this->module_.get()))) {
           errorf(pos,

src/wasm/wasm-opcodes.cc

@@ -36,8 +36,8 @@ std::ostream& operator<<(std::ostream& os, const FunctionSig& sig) {
 bool IsJSCompatibleSignature(const FunctionSig* sig, const WasmModule* module,
                              const WasmFeatures& enabled_features) {
   for (auto type : sig->all()) {
-    // TODO(7748): Allow structs, arrays, and rtts when their JS-interaction is
-    // decided on.
+    // Structs and arrays may only be passed via externref.
+    // Rtts are implicit and can not be used explicitly.
     if (type == kWasmS128 || type.is_rtt() ||
         (type.has_index() && !module->has_signature(type.ref_index()))) {
       return false;