Rename `deadline` logger field to `timeout` (#2184)

[jquirke]

In #2185 we introduced logging of the ttl of the request, but under the deadline logging tag.

It is a more appropriate name for a relative duration to use the term timeout, and avoid confusion.

[codecov[bot]]

Codecov Report

Base: 85.28% // Head: 85.29% // Increases project coverage by +0.01% :tada:

Coverage data is based on head (2da4f6a) compared to base (634d9e3). Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## dev #2189 +/- ## ========================================== + Coverage 85.28% 85.29% +0.01% ========================================== Files 269 269 Lines 15399 15399 ========================================== + Hits 13133 13135 +2 + Misses 1845 1844 -1 + Partials 421 420 -1 ``` | [Impacted Files](https://codecov.io/gh/yarpc/yarpc-go/pull/2189?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=yarpc) | Coverage Δ | | |---|---|---| | [internal/observability/call.go](https://codecov.io/gh/yarpc/yarpc-go/pull/2189/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=yarpc#diff-aW50ZXJuYWwvb2JzZXJ2YWJpbGl0eS9jYWxsLmdv) | `94.06% <100.00%> (ø)` | | | [dispatcher\_startup.go](https://codecov.io/gh/yarpc/yarpc-go/pull/2189/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=yarpc#diff-ZGlzcGF0Y2hlcl9zdGFydHVwLmdv) | `91.07% <0.00%> (-1.79%)` | :arrow_down: | | [internal/observability/graph.go](https://codecov.io/gh/yarpc/yarpc-go/pull/2189/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=yarpc#diff-aW50ZXJuYWwvb2JzZXJ2YWJpbGl0eS9ncmFwaC5nbw==) | `93.75% <0.00%> (+0.62%)` | :arrow_up: | | [peer/hashring32/internal/hashring32/hashring32.go](https://codecov.io/gh/yarpc/yarpc-go/pull/2189/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=yarpc#diff-cGVlci9oYXNocmluZzMyL2ludGVybmFsL2hhc2hyaW5nMzIvaGFzaHJpbmczMi5nbw==) | `97.29% <0.00%> (+1.08%)` | :arrow_up: | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=yarpc). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=yarpc)

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[jronak]

Thanks, @rabbbit, timeout sounds appropriate in this case. Stamped!