Document SHOW STATISTICS using JSON and INJECT STATISTICS

[glennfawcett]

Is your feature request related to a problem? Please describe.
Need to Document

• SHOW STATISTICS USING JSON FOR TABLE ...
• ALTER TABLE... INJECT STATISTICS

Describe the solution you'd like
Docs to be created as mentioned above

Additional context

This is an example of what I am doing to copy statistics from one table to another...

cockroach sql -e 'show statistics using json for table kv.kv' --insecure --format raw | grep -v '^#' | while read s do echo "ALTER TABLE kv.kv2 INJECT STATISTICS '$s';" | cockroach sql --insecure done

Jira issue: CRDB-7865

[github-actions]

We have marked this issue as stale because it has been inactive for
18 months. If this issue is still relevant, removing the stale label
or adding a comment will keep it active. Otherwise, we'll close it in
10 days to keep the issue queue tidy. Thank you for your contribution
to CockroachDB!

[sheaffej]

This is still relevant, as the SHOW STATISTICS docs do not currently show the syntax for USING JSON, nor is there a page that I can find that describes how to inject these statistics into another cluster.