In-place array repetition changes values without updating serialized TOML #646

On current master (858186a), in-place array repetition changes the Python list but leaves the serialized TOML unchanged:

import tomlkit

doc = tomlkit.parse("a = [1, 2]\n")
a = doc["a"]
a *= 0
assert a == []
print(tomlkit.dumps(doc))  # still a = [1, 2]

With a *= 2, the values become [1, 2, 1, 2], but the document still serializes [1, 2]. Negative repetition similarly clears the list without clearing the rendered values. The array remains the same object attached to the document.

I plan to synchronize this existing list operation by using the array's current clear() / extend() paths, with tests that compare values, serialization and subsequent mutation. This does not change sorting/reordering behavior discussed in #233.

Prepared with AI assistance. I found no repetition-related issue or PR; please flag any overlapping work.