chore(deps): update module mvdan.cc/gofumpt to v0.9.0

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
mvdan.cc/gofumpt	v0.8.0 -> v0.9.0

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Warning

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Release Notes

mvdan/gofumpt (mvdan.cc/gofumpt)

v0.9.0

Compare Source

This release is based on Go 1.25's gofmt, and requires Go 1.24 or later.

A new rule is introduced to "clothe" naked returns for the sake of clarity.
While there is nothing wrong with naming results in function signatures,
using lone return statements can be confusing to the reader.

Go 1.25's ignore directives in go.mod files are now obeyed;
any directories within the module matching any of the patterns
are now omitted when walking directories, such as with gofumpt -w ..

Module information is now loaded via Go's x/mod/modfile package
rather than executing go mod edit -json, which is way faster.
This should result in moderate speed-ups when formatting many directories.

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Configuration

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♻ Rebasing: Whenever PR is behind base branch, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

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• If you want to rebase/retry this PR, check this box

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.9%. Comparing base (295fbdc) to head (d6fb753).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #7292     +/-   ##
=======================================
- Coverage   82.9%   82.9%   -0.1%     
=======================================
  Files        265     265             
  Lines      24894   24894             
=======================================
- Hits       20644   20642      -2     
- Misses      3875    3877      +2     
  Partials     375     375             

Files with missing lines	Coverage Δ
baggage/baggage.go	99.3% <100.0%> (ø)
semconv/internal/http.go	100.0% <100.0%> (ø)
semconv/internal/v2/http.go	100.0% <100.0%> (ø)
semconv/internal/v2/net.go	100.0% <100.0%> (ø)
semconv/internal/v3/http.go	100.0% <100.0%> (ø)
semconv/internal/v3/net.go	100.0% <100.0%> (ø)
semconv/internal/v4/http.go	100.0% <100.0%> (ø)
semconv/internal/v4/net.go	100.0% <100.0%> (ø)

... and 2 files with indirect coverage changes

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[dmathieu]

@open-telemetry/go-approvers could I get a review here, since I had to push a non-automated commit to fix the linter?