trie: enforce monotonic range in prover and return end marker (#21130)

* trie: add hasRightElement indicator

* trie: ensure the range is monotonic increasing

* trie: address comment and fix lint

* trie: address comment

* trie: make linter happy

Co-authored-by: Péter Szilágyi <peterke@gmail.com>
# Conflicts:
#	trie/proof.go
#	trie/proof_test.go