Add an EnumMaskBase type (#6053)

This is a bit of an experiment to see if there's a reasonable way to
write a shared enum type, rather than writing per-case wrappers for
things like `HasTypeQualifiers` or the printing. I think it's a bit
borderline complexity right now, but I'm not sure I can reduce it much
further.

This changes from things like `Internal::EnumClassName##RawEnum` to
`Internal::EnumClassName##Data::RawEnum` so that the enum entries can
have back references to bit shifts without needing to know the
containing type name. Because I'm trying to reduce duplication between
mask and non-mask enums, I did this to non-mask enums too.

This was motivated by #6035 adding another enum mask (which will grow
more entries, and is intended to switch if this is accepted), but I'm
not using that PR as a base here because I didn't want the merge
dependency.

toolchain/parse/node_category.cpp

@@ -8,30 +8,7 @@
 
 namespace Carbon::Parse {
 
-// Returns a string form of the node category for printing.
-static auto NodeCategoryToString(NodeCategory::RawEnumType category)
-    -> llvm::StringLiteral {
-#define CARBON_NODE_CATEGORY_TO_STRING(Name) \
-  case NodeCategory::Name:                   \
-    return #Name;
-
-  switch (category) {
-    CARBON_NODE_CATEGORY(CARBON_NODE_CATEGORY_TO_STRING)
-    CARBON_NODE_CATEGORY_TO_STRING(None)
-  }
-
-#undef CARBON_NODE_CATEGORY_TO_STRING
-}
-
-auto NodeCategory::Print(llvm::raw_ostream& out) const -> void {
-  llvm::ListSeparator sep("|");
-  auto value = value_;
-  do {
-    // The lowest set bit in the value, or 0 (`None`) if no bits are set.
-    auto lowest_bit = static_cast<RawEnumType>(value & -value);
-    out << sep << NodeCategoryToString(lowest_bit);
-    value &= ~lowest_bit;
-  } while (value);
-}
+CARBON_DEFINE_ENUM_MASK_NAMES(NodeCategory) = {
+    CARBON_NODE_CATEGORY(CARBON_ENUM_MASK_NAME_STRING)};
 
 }  // namespace Carbon::Parse