sql: add tracing for locks requested by a scan

[mw5h]

Previously, we would only log the spans requested by a scan. To provide additional visibility about lock acquisition, we now include information about locking modes requested by a scan.

Fixes: #115016

Release note: None

[blathers-crl[bot]]

It looks like your PR touches production code but doesn't add or edit any test code. Did you consider adding tests to your PR?

_{:owl: Hoot! I am a Blathers, a bot for CockroachDB. My owner is dev-inf.}

[cockroach-teamcity]

All committers have signed the CLA.

[cockroach-teamcity]

This change is 

[mw5h]

nit: what's reason for incrementing bytesHint by 1?

I must've typoed that while updating the print statement. I was sitting here wondering "why 1025? that's a weird size."

[mw5h]

bors r+

[craig[bot]]

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