Improve documentation of code generator

[joaopgrassi]

There are a couple of issues about our current code generator documentation. In general, I feel the process to get the things working is not clear. There are several arguments that are not documented at all, and folks need either to ask here, or dig into the code themselves to find things out.

I can tell from my own experience as a "first timer". It was particularly painful for me when I was trying to get it to work for the .NET SDK open-telemetry/opentelemetry-dotnet#2069.

I feel we need to cover in the docs:

• All the parameters the tool accepts and what they do
• Examples of how to use it to generate code files from YAML
  • Here we could either link to the existing one we know in Java + another language as JS

[ezinneanne]

Hello, can I work on this?

[joaopgrassi]

Hi @ezinneanne sure! Feel free to work on it and reach out if something is unclear.

[joaopgrassi]

@ezinneanne are you working on this? Let me know so I can assign it to you then. Thank you!

[ezinneanne]

Hello, I would love to work on this but am preoccupied at the moment. You can assign it to someone else. Thank you @joaopgrassi

[lmolkova]

I think this was covered in #243 and will be fully merged in #295

[lmolkova]

There were a lot of docs improvements in the 0.24.0 release - https://github.com/open-telemetry/build-tools/blob/v0.24.0/semantic-conventions/README.md#code-generator

I think we can still improve it further documenting a few remaining filters and tests, so I'm keeping it open.