Support allowReserved keyword for query parameters

[actinium15]

OpenAPI 3.1 [0] (and 3.0 as well [1]) notes:

Determines whether the parameter value SHOULD allow reserved characters, as defined by RFC3986 :/?#[]@!$&'()*+,;= to be included without percent-encoding. This property only applies to parameters with an in value of query. The default value is false.

The way I understand it, it means when allowReserved is set to true for any given query parameter, any , that appear in the value are sent as-is (i.e., without percent-encoding). RapiDoc doesn't seem to honor it currently.

As an example, consider the API definition at [2]. If I were to place this definition in https://editor.swagger.io/ and 'try', the request URI (as seen on Browser DevTools' Network panel) is:

https://example.com/my/api?c=100,100,200,200

However, if I remove/comment-out allowReserved: true for query param c (or set allowReserved: false) this is what the request URI becomes:

https://example.com/my/api?c=100%2C100%2C200%2C200

This is not how RapiDoc behaves, though (there's no special handling for allowReserved in [3] as far as I can tell).

The reason might be due to api-request.js [3] relying on URLSearchParams to build the URI. URLSearchParams assumes form-urlencoded input [4] and encodes all reserved characters.
Since [3] uses it directly, there's no room to honor allowReserved attribute in the current impl.

NB: Quoting from the section 3.4 (Query) of RFC 3986:

   The query component is indicated by the first question
   mark ("?") character and terminated by a number sign ("#") character
   or by the end of the URI.
      query       = *( pchar / "/" / "?" )

Then, in Appendix A:

   pchar         = unreserved / pct-encoded / sub-delims / ":" / "@"
   query         = *( pchar / "/" / "?" )
...
   sub-delims    = "!" / "$" / "&" / "'" / "(" / ")"
                 / "*" / "+" / "," / ";" / "="

The way I'm reading it, it is allowed for sub-delims to appear non-percent-encoded in the query part of the URI. Setting allowReserved property on a query-parameter in the API definition should prevent its percent-encoding the HTTP request created by RapiDoc.

[0] https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.1.0.md#fixed-fields-10 (search for allowReserved)
[1] https://swagger.io/docs/specification/serialization/ (search for allowReserved)
[2]

openapi: 3.0.3
info:
  title: test
  version: 0.0.1
servers:
  - url: 'https://example.com'
components:
  schemas:
    CommaSeparatedQueryParam:
      type: string
      pattern: '(\d+,\d+,\d+,\d+)'
      example: 100,100,200,200
paths:
  /my/api:
    get:
      summary: test api
      operationId: my/test/api
      parameters:
        - in: query
          name: c
          description: comma-separated list of four numbers
          allowReserved: true
          schema:
            $ref: '#/components/schemas/CommaSeparatedQueryParam'
      responses:
        '200':
          description: OK
          content:
            image/*: # Media type
              schema: 
                type: string
                format: binary

[3] https://github.com/mrin9/RapiDoc/blob/master/src/components/api-request.js
[4]

URLSearchParams object uses the application/x-www-form-urlencoded format underneath... URLSearchParams objects will percent-encode anything in the application/x-www-form-urlencoded percent-encode set, and will encode U+0020 SPACE as U+002B (+).

(from https://url.spec.whatwg.org/#example-constructing-urlsearchparams)