docs: align unauthenticated note tutorial with 5-account source

[memosr]

The account count in this tutorial disagreed with the real program in three
different ways:

• the doc's code block sets number_of_accounts = 2
• rust-client/src/bin/unauthenticated_note_transfer.rs sets it to 5
• the doc's expected output lists 10 accounts and 9 transfers

The source is canonical, and the tutorial's own transfer chain confirms it:
it runs account_0 to account_4, which is 5 accounts and 4 transfers.

Changes:

• code block now uses 5, matching the source
• expected output trimmed to accounts 0-4 and tx 1-4
• closing balances trimmed accordingly, with the terminal 20 landing on
  account_4 instead of account_9
• removed the blocks: [...] line: no println! in the current source
  emits it, so it is leftover output from an older version of the program
• replaced the hardcoded per-iteration and total durations with
  <duration> placeholders, matching the <account_N_id> style already
  used in this block. Trimming 9 iterations to 4 would have made the old
  totals wrong, and inventing replacement timings seemed worse than not
  claiming a number

Left untouched deliberately: the MidenScan tx hashes and the Latest block
height. Those are ordinary per-run values and unrelated to the account count.

Docs-only change. cargo test --doc in docs/ passes (17 passed, 0 failed).
Ran prettier --write per CONTRIBUTING.md; the file was already conformant.