update generate-docs script

[celenechang]

What does this PR do?

Refine generate-docs script so that

1. Parameter name is not repeated in first word of description for easier readability
2. Accepts description overrides in a JSON file, for parameters that are not defined in our types file (i.e. imports)

This PR also edits a couple of our internal descriptions based on recommendations from the docs team

Motivation

Improving our documentation

Additional Notes

Anything else we should know when reviewing?

Minimum Agent Versions

Are there minimum versions of the Datadog Agent and/or Cluster Agent required?

• Agent: vX.Y.Z
• Cluster Agent: vX.Y.Z

Describe your test plan

Write there any instructions and details you may have to test your PR.

Checklist

• PR has at least one valid label: bug, enhancement, refactoring, documentation, tooling, and/or dependencies
• PR has a milestone or the qa/skip-qa label

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 33 lines in your changes missing coverage. Please review.

Project coverage is 48.64%. Comparing base (58f766a) to head (4163ed2).

Files with missing lines	Patch %	Lines
hack/generate-docs.go	0.00%	33 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1503      +/-   ##
==========================================
- Coverage   48.70%   48.64%   -0.06%     
==========================================
  Files         224      224              
  Lines       19845    19869      +24     
==========================================
  Hits         9666     9666              
- Misses       9670     9694      +24     
  Partials      509      509              

Flag	Coverage Δ
unittests	48.64% <0.00%> (-0.06%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
api/datadoghq/v2alpha1/datadogagent_types.go	100.00% <ø> (ø)
hack/generate-docs.go	0.00% <0.00%> (ø)

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