Fix metrics descriptions: dupes and rates

[andf-crl]

Describe the problem

8 metrics have the word replica duplicated in the description. See To Reproduce.

This is important because DOCS will shortly be populating metrics descriptions exclusively from chartcatalog output i.e. verbatim from what you write.

While in there, please update any metrics descriptions that are rates but don't say so to say so, and audit other metrics within your purview for similar. I can help with this effort -- please ping me.

For starters:

range.snapshots.rebalancing.rcvd-bytes | Number of rebalancing snapshot bytes received
range.snapshots.rebalancing.sent-bytes | Number of rebalancing snapshot bytes sent
range.snapshots.recovery.rcvd-bytes | Number of recovery snapshot bytes received
range.snapshots.recovery.sent-bytes | Number of recovery snapshot bytes sent

These are all rates: number per second.

To Reproduce

curl -s http://localhost:8080/_admin/v1/chartcatalog | grep 'replica replica'

Expected behavior
Descriptions are as accurate as possible!

Environment:

• CockroachDB v22.2.0-rc.3

Additional context
Thanks very much team! Happy to help audit any and all metrics descriptions, or to pair on this work with engineering.

Jira issue: CRDB-22056