add support for empty response

[ubogdan]

Describe the PR
Add support for "nil" type for the empty response

Relation issue
#941 #1163

Additional context
NONE

[codecov]

Codecov Report

Merging #989 (3861e45) into master (0bbefcf) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #989   +/-   ##
=======================================
  Coverage   92.50%   92.51%           
=======================================
  Files           8        8           
  Lines        1921     1923    +2     
=======================================
+ Hits         1777     1779    +2     
  Misses         81       81           
  Partials       63       63           

Impacted Files	Coverage Δ
schema.go	100.00% <ø> (ø)
operation.go	94.26% <100.00%> (+0.01%)	⬆️

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[cristian-aldea]

Hello, I wanted to make a PR to document this features that was added.

Do I just need to update the README?
Do I need to update any other parts of this project to update this page? https://swaggo.github.io/swaggo.io/declarative_comments_format/api_operation.html

[ubogdan]

Technically all the features need to be updated in README.md and README_zh-CN.md.
I'm ok if you update only the English version.

[cristian-aldea]

I'll see if I can update both.

Thanks, I'll send the PR sometime this weekend

[cristian-aldea]

There seems to be some discrepancy between the content for "Param Type" in https://swaggo.github.io/swaggo.io/declarative_comments_format/api_operation.html and in the README.md. Which is the source of truth?

"Param Type" in README:

- query
- path
- header
- body
- formData

"Param Type" on website:

* object (struct)
* string (string)
* integer (int, uint, uint32, uint64)
* number (float32)
* boolean (bool)
* array

The content from https://swaggo.github.io/swaggo.io/ seems more accurate, but where does it come from?