rewording from arma

Oops. Feature Sebastian kindly added a few months back. Looks like it didn't
make it into the spec.

  https://trac.torproject.org/projects/tor/ticket/14784

Patch by Tim Wilson-Brown ("teor").

Use _LEN rather than _LENGTH for field lengths in 224-rend-spec-ng.txt.
(8 replacements made.)

Patch by Tim Wilson-Brown ("teor").

Fix misspellings, inconsistent field names, and missing INT_8()
specifiers.

Patch by Tim Wilson-Brown ("teor").

now try to phrase it in a less confusing way.

The salt serves the same purpose as 'nonce' did in secret_input, by
ensuring that the KDF does not produce the same output twice even in
event of accidental revision counter replay.

Pointed out by DonnchaC.

Minor revisions for the new NETWORK_LIVENESS event...

  * Include a note about the version when this is being added.

  * No need to say new fields are allowed. This is said near the start of
    section 4.1...

    "Clients MUST tolerate events with arguments and keywords they do not
    recognize"

  * Rejigger the spec's style a tad to be more like other events.

Commit ba30c1df accidently reverted dgoulet's change from aaf2434a to note that
HSFETCH can result in the address being 'UNKNOWN'.

David Goulet authored Feb 10, 2015 and Nick Mathewson committed Apr 23, 2015

Ref: #14845

Signed-off-by: David Goulet <dgoulet@ev0ke.net>

This adds the HSFETCH command as well as the HS_DESC_CONTENT event to the
control specification.

The HS_DESC event is also changed a bit to fit the HSFETCH command case.

Ref.: #14847

Signed-off-by: David Goulet <dgoulet@ev0ke.net>

Fixes #15276.