Move the comment of the duration into the doc.

[wu-sheng]

Please answer these questions before submitting pull request

• Why submit this pull request?
  Doc improvement.

• Related issues
  Resolve Add document about time condition in GraphQL #4267 and Rocketbot time range and interface condition correspondence #4266

[codecov-io]

Codecov Report

Merging #4301 into master will increase coverage by 0.06%.
The diff coverage is 23.88%.

@@            Coverage Diff             @@
##           master    #4301      +/-   ##
==========================================
+ Coverage   26.86%   26.92%   +0.06%     
==========================================
  Files        1162     1168       +6     
  Lines       25398    25465      +67     
  Branches     3627     3634       +7     
==========================================
+ Hits         6822     6857      +35     
- Misses      17971    17999      +28     
- Partials      605      609       +4

Impacted Files	Coverage Δ
...ywalking/apm/plugin/avro/ResponderInterceptor.java	0% <0%> (ø)
.../apm/network/trace/component/ComponentsDefine.java	0% <0%> (ø)	⬆️
.../skywalking/apm/plugin/avro/SWClientRPCPlugin.java	0% <0%> (ø)
.../skywalking/apm/plugin/avro/SWServerRPCPlugin.java	0% <0%> (ø)
.../apm/plugin/avro/SpecificRequestorInterceptor.java	100% <100%> (ø)
...g/apm/plugin/avro/GenericRequestorInterceptor.java	100% <100%> (ø)
...ng/apm/plugin/avro/AbstractRequestInterceptor.java	15% <15%> (ø)
... and 5 more

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