Update CBO docs to list more supported statements

A bit more work to address #3998.

Summary of changes:

- Edit the 'Supported statements' section of the ['Cost-based
  Optimizer'][1] page to add:

  - Add FILTER per cockroachdb/cockroach#34077

  - Add DELETE per cockroachdb/cockroach#34522

  - Add `INSERT .. ON CONFLICT` variants per cockroachdb/cockroach#33339

[1]: http://www.cockroachlabs.com/docs/v2.2/cost-based-optimizer.html

_includes/v2.2/sql/settings/settings.md

@@ -62,7 +62,6 @@
 <tr><td><code>sql.defaults.default_int_size</code></td><td>integer</td><td><code>8</code></td><td>the size, in bytes, of an INT type</td></tr>
 <tr><td><code>sql.defaults.distsql</code></td><td>enumeration</td><td><code>1</code></td><td>default distributed SQL execution mode [off = 0, auto = 1, on = 2, 2.0-off = 3, 2.0-auto = 4]</td></tr>
 <tr><td><code>sql.defaults.experimental_automatic_statistics</code></td><td>boolean</td><td><code>false</code></td><td>default experimental automatic statistics mode</td></tr>
-<tr><td><code>sql.defaults.experimental_optimizer_mutations</code></td><td>boolean</td><td><code>false</code></td><td>default experimental_optimizer_mutations mode</td></tr>
 <tr><td><code>sql.defaults.experimental_vectorize</code></td><td>enumeration</td><td><code>0</code></td><td>default experimental_vectorize mode [off = 0, on = 1, always = 2]</td></tr>
 <tr><td><code>sql.defaults.optimizer</code></td><td>enumeration</td><td><code>1</code></td><td>default cost-based optimizer mode [off = 0, on = 1, local = 2]</td></tr>
 <tr><td><code>sql.defaults.results_buffer.size</code></td><td>byte size</td><td><code>16 KiB</code></td><td>size of the buffer that accumulates results for a statement or a batch of statements before they are sent to the client. Note that auto-retries generally only happen while no results have been delivered to the client, so reducing this size can increase the number of retriable errors a client receives. On the other hand, increasing the buffer size can increase the delay until the client receives the first result row. Updating the setting only affects new connections. Setting to 0 disables any buffering.</td></tr>
@@ -92,6 +91,6 @@
 <tr><td><code>trace.debug.enable</code></td><td>boolean</td><td><code>false</code></td><td>if set, traces for recent requests can be seen in the /debug page</td></tr>
 <tr><td><code>trace.lightstep.token</code></td><td>string</td><td><code></code></td><td>if set, traces go to Lightstep using this token</td></tr>
 <tr><td><code>trace.zipkin.collector</code></td><td>string</td><td><code></code></td><td>if set, traces go to the given Zipkin instance (example: '127.0.0.1:9411'); ignored if trace.lightstep.token is set.</td></tr>
-<tr><td><code>version</code></td><td>custom validation</td><td><code>2.1-4</code></td><td>set the active cluster version in the format '<major>.<minor>'.</td></tr>
+<tr><td><code>version</code></td><td>custom validation</td><td><code>2.1-4</code></td><td>set the active cluster version in the format '{major}.{minor}'.</td></tr>
 </tbody>
 </table>

v2.2/cost-based-optimizer.md

@@ -74,16 +74,17 @@ pq: unsupported statement: *tree.Insert
 The cost-based optimizer supports most SQL statements. Specifically, the following types of statements are supported:
 
 - [`CREATE TABLE`](create-table.html)
-- [`INSERT`](insert.html)
-- [Sequences](create-sequence.html)
-- [Views](views.html)
-
-The following additional statements are supported by the optimizer if you set the `experimental_optimizer_updates` [cluster setting](set-cluster-setting.html) to `true`:
-
 - [`UPDATE`](update.html)
+- [`INSERT`](insert.html), including:
+  - `INSERT .. ON CONFLICT DO NOTHING`
+  - `INSERT .. ON CONFLICT .. DO UPDATE`
 - [`UPSERT`](upsert.html)
+- [`FILTER`](filter.html)
+- [`DELETE`](delete.html)
+- [Sequences](create-sequence.html)
+- [Views](views.html)
 
-For instructions showing how to check whether a particular query will be run with the cost-based optimizer, see the [View query plan](#view-query-plan) section.
+This is not meant to be an exhaustive list. To check whether a particular query will be run with the cost-based optimizer, follow the instructions in the [View query plan](#view-query-plan) section.
 
 ## Table statistics