Remaining per-page accuracy findings (grammar, generics, and eight stdlib pages)

[O6lvl4]

Leftovers from the per-page audit — every item below was reproduced by running it. The cross-cutting defects (lambda syntax, function-type notation, pipe placeholder, auto-import classification, operator precedence) are already fixed in a33359f; these are the ones still open.

reference/grammar.md

• Missing operators from the operator list: >>, !, ?, ??, ?.
• Missing built-in types: Bytes, Matrix, RawPtr, Never
• Auto-import list omits error, datetime, int8…uint64, float32
• "next line starts with . (method chaining)" continuation rule — a leading . is a parse error. Leading |> does work.
• not is listed among the binary operators; it is unary

guide/generics.md

The two bound examples cannot be used as written:

• fn show[T: Repr](item: T) — Repr is not auto-derived for a bound. Calling it gives type 'Point' does not implement protocol 'Repr', and built-in types like Int can never satisfy it.
• fn compare[T: Ord](a: T, b: T) -> Bool = a < b — declares fine but is uncallable; Int does not implement Ord, and a user type declared : Ord fails in codegen.

The only bounds built-in types actually satisfy are Numeric and Hash. Suggest rewriting both examples against a user-defined protocol (the Serializable shape in protocols.md, which does work).

stdlib pages

• json: get is described as fetching a nested value — it is flat top-level only. get_int / as_int are described as returning none for a non-integer — they truncate floats (2.7 → some(2)). to_map missing from the function table. JsonPath cannot be written as a type annotation.
• bytes: set is described as mutating in place — it returns a new Bytes and leaves the original alone even for a var binding (the in-place one is the undocumented set_at). push really takes mut b: Bytes, so it needs a var. The is_empty([]) example does not compile. The whole current surface (read_uint16/32, read_int32, read_float32, write_*, set_*, Endian) is undocumented.
• list: pop is described as discarding the last element — it returns it. The filter_map example passes int.parse, which returns Result, not Option. list.is_empty([]) needs an annotated empty list.
• map: map.new() needs a type annotation to compile as shown.
• string: slice is documented 3-arg; the third parameter has a default, so the 2-arg form works and is undocumented.
• option / result: option.is_none(none), result.is_err(err(…)) and result.to_err_option(err(…)) all fail to build (filed upstream as almide#899). error.context's error type is fixed to String, not generic as documented, and its example uses result as a variable name, which is a module.
• datetime / matrix: the reference examples contradict their own setup values (a timestamp fixed at 12:00:00 whose minute is documented as 30; a matrix that is 3×4 in one example and 2×2 in the next).
• testing: omits the built-in assert, assert_eq, assert_ne (no import needed) — the most-used assertions. assert_some / assert_ok are generic natively; the Option[String] / Result[String, String] restriction the page states is the WASM-only one, and assert_throws has no WASM implementation at all.