anchors: follow up changes after initial zero fee anchors merge (#903)

We can remove references to anchors in a few places, and you need
static key in order to support it, so that reference is redundant.

02-peer-protocol.md

@@ -458,7 +458,7 @@ use `option_static_remotekey`, `option_anchor_outputs` or
 
 `option_anchors_zero_fee_htlc_tx` is considered superior to
 `option_anchor_outputs`, which again is considered superior to
-`option_static_remotekey`, and the superior one is is favored if more than one
+`option_static_remotekey`, and the superior one is favored if more than one
 is negotiated.
 
 ### The `funding_locked` Message
@@ -1352,7 +1352,7 @@ The sending node:
   next `commitment_signed` it expects to receive.
   - MUST set `next_revocation_number` to the commitment number of the
   next `revoke_and_ack` message it expects to receive.
-  - if `option_static_remotekey` or `option_anchors` applies to the commitment
+  - if `option_static_remotekey` applies to the commitment
     transaction:
     - MUST set `my_current_per_commitment_point` to a valid point.
   - otherwise:
@@ -1400,8 +1400,7 @@ A node:
       - SHOULD send an `error` and fail the channel.
 
  A receiving node:
-  - if `option_static_remotekey` or `option_anchors` applies to the commitment
-    transaction:
+  - if `option_static_remotekey` applies to the commitment transaction:
     - if `next_revocation_number` is greater than expected above, AND
     `your_last_per_commitment_secret` is correct for that
     `next_revocation_number` minus 1:

09-features.md

@@ -39,7 +39,7 @@ The Context column decodes as follows:
 | 16/17 | `basic_mpp`                      | Node can receive basic multi-part payments                | IN9      | `payment_secret`  | [BOLT #4][bolt04-mpp]                 |
 | 18/19 | `option_support_large_channel`   | Can create large channels                                 | IN       |                   | [BOLT #2](02-peer-protocol.md#the-open_channel-message) |
 | 20/21 | `option_anchor_outputs`          | Anchor outputs                                            | IN       | `option_static_remotekey` | [BOLT #3](03-transactions.md)         |
-| 22/23 | `option_anchors_zero_fee_htlc_tx` | Anchor commitment type with zero fee HTLC transactions   | IN       |                   | [BOLT #3][bolt03-htlc-tx], [lightning-dev][ml-sighash-single-harmful]|
+| 22/23 | `option_anchors_zero_fee_htlc_tx` | Anchor commitment type with zero fee HTLC transactions   | IN       | `option_static_remotekey` | [BOLT #3][bolt03-htlc-tx], [lightning-dev][ml-sighash-single-harmful]|
 | 26/27 | `option_shutdown_anysegwit`         | Future segwit versions allowed in `shutdown`              | IN       |                   | [BOLT #2][bolt02-shutdown]   |
 | 44/45 | `option_channel_type`            | Node supports the `channel_type` field in open/accept     | IN       |                   | [BOLT #2](02-peer-protocol.md#the-open_channel-message) |
 | 48/49 | `option_payment_metadata` | Payment metadata in tlv record | 9 | | [BOLT #11](11-payment-encoding.md#tagged-fields)