add a json param in the callbacks and openapi docs

[sansyrox]

No description provided.

[randomseed42]

Thanks for opening this issue, I'll just post my example here to explain the scenario:

• only if you add body: Body in the route method, it will show Request body in /docs, otherwise you can not test your route in /docs
• the body arg is not useful since it is already converted to json as request.json()

from robyn import Robyn, Request
from robyn.types import Body


app = Robyn(__file__)


@app.post('/api/c2f')
async def c2f(request: Request) -> dict | None:
    data = request.json()
    if 'celsius' not in data:
        return
    return {'fahrenheit': float(data['celsius']) * 9 / 5 + 32}


@app.post('/api/f2c')
async def f2c(request: Request, body: Body) -> dict | None:
    data = request.json()
    if 'fahrenheit' not in data:
        return
    return {'celsius': (float(data['fahrenheit']) - 32) * 5 / 9}


if __name__ == '__main__':
    app.start(host='127.0.0.1', port=8000)