kv: include RangeID in rangefeed goroutine stacks

[nvanbenschoten]

This commit includes the RangeID in each of a rangefeed processor and
its registations' associated goroutine stacks. This is a cheap and easy
way to get better observability into the ranges that have active
rangefeeds. It also tells us where those goroutines are spending their
time.

This will also become easier to use in Go 1.17, which improved the
format of stack traces.

[cockroach-teamcity]

This change is 

[erikgrinaker]

Thanks, this'll be useful!

[nvanbenschoten]

bors r+

[craig]

Build failed:

• GitHub CI (Cockroach)

[nvanbenschoten]

TestFullClusterBackup flake.

bors r+

[craig]

Build succeeded:

• GitHub CI (Cockroach)

[blathers-crl]

Encountered an error creating backports. Some common things that can go wrong:

1. The backport branch might have already existed.
2. There was a merge conflict.
3. The backport branch contained merge commits.

You might need to create your backport manually using the backport tool.

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error creating merge commit from 1306da5 to blathers/backport-release-20.2-68442: POST https://api.github.com/repos/cockroachdb/cockroach/merges: 409 Merge conflict []

you may need to manually resolve merge conflicts with the backport tool.

Backport to branch 20.2.x failed. See errors above.

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error creating merge commit from 1306da5 to blathers/backport-release-21.1-68442: POST https://api.github.com/repos/cockroachdb/cockroach/merges: 409 Merge conflict []

you may need to manually resolve merge conflicts with the backport tool.

Backport to branch 21.1.x failed. See errors above.

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