chore: fix jsdocs

[atian25]

Checklist

• npm test passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

Affected core subsystem(s)

Description of change

[codecov]

Codecov Report

Merging #3627 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master   #3627   +/-   ##
======================================
  Coverage     100%    100%           
======================================
  Files          32      32           
  Lines         921     921           
======================================
  Hits          921     921

Impacted Files	Coverage Δ
app/extend/request.js	100% <ø> (ø)	⬆️
lib/egg.js	100% <ø> (ø)	⬆️
app/extend/helper.js	100% <ø> (ø)	⬆️
app/extend/response.js	100% <ø> (ø)	⬆️
lib/agent.js	100% <ø> (ø)	⬆️
lib/core/base_context_logger.js	100% <ø> (ø)	⬆️
app/extend/context.js	100% <ø> (ø)	⬆️
lib/application.js	100% <ø> (ø)	⬆️

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