Fix 2448 remove custom formatter

[mroderick]

Fix 2448: remove custom formatter … Remove option to pass a custom formatter.

The sub libraries of Sinon has long moved on to use util.inspect from Node. By using that in Sinon itself, we align all the libraries.

See #2448 for discussion

[codecov[bot]]

Codecov Report

Base: 95.97% // Head: 95.95% // Decreases project coverage by -0.02% :warning:

Coverage data is based on head (0036e00) compared to base (49ef930). Patch coverage: 100.00% of modified lines in pull request are covered.

:exclamation: Current head 0036e00 differs from pull request most recent head 5c06c50. Consider uploading reports for the commit 5c06c50 to get more accurate results

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #2480 +/- ## ========================================== - Coverage 95.97% 95.95% -0.03% ========================================== Files 39 38 -1 Lines 1888 1878 -10 ========================================== - Hits 1812 1802 -10 Misses 76 76 ``` | Flag | Coverage Δ | | |---|---|---| | unit | `95.95% <100.00%> (-0.03%)` | :arrow_down: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=sinonjs#carryforward-flags-in-the-pull-request-comment) to find out more. | [Impacted Files](https://codecov.io/gh/sinonjs/sinon/pull/2480?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=sinonjs) | Coverage Δ | | |---|---|---| | [lib/sinon.js](https://codecov.io/gh/sinonjs/sinon/pull/2480/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=sinonjs#diff-bGliL3Npbm9uLmpz) | `100.00% <ø> (ø)` | | | [lib/sinon/assert.js](https://codecov.io/gh/sinonjs/sinon/pull/2480/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=sinonjs#diff-bGliL3Npbm9uL2Fzc2VydC5qcw==) | `100.00% <100.00%> (ø)` | | | [lib/sinon/mock-expectation.js](https://codecov.io/gh/sinonjs/sinon/pull/2480/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=sinonjs#diff-bGliL3Npbm9uL21vY2stZXhwZWN0YXRpb24uanM=) | `95.23% <100.00%> (ø)` | | | [lib/sinon/proxy-call.js](https://codecov.io/gh/sinonjs/sinon/pull/2480/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=sinonjs#diff-bGliL3Npbm9uL3Byb3h5LWNhbGwuanM=) | `98.19% <100.00%> (ø)` | | | [lib/sinon/proxy.js](https://codecov.io/gh/sinonjs/sinon/pull/2480/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=sinonjs#diff-bGliL3Npbm9uL3Byb3h5Lmpz) | `83.22% <100.00%> (ø)` | | | [lib/sinon/spy-formatters.js](https://codecov.io/gh/sinonjs/sinon/pull/2480/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=sinonjs#diff-bGliL3Npbm9uL3NweS1mb3JtYXR0ZXJzLmpz) | `98.50% <100.00%> (ø)` | | 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=sinonjs). 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=sinonjs)

:umbrella: View full report at Codecov.
:loudspeaker: Do you have feedback about the report comment? Let us know in this issue.

[mroderick]

This has been published to the npm registry as v15.0.0