[REQ] [C][Client] Generate document automatically for C client

[ityuhui]

Describe the solution you'd like

I'd like to add the templates to auto-generate documentation for C client
Just like ruby client https://github.com/OpenAPITools/openapi-generator/blob/master/samples/client/petstore/ruby/docs/PetApi.md
and C++ generators do.

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[ityuhui]

@wing328 @zhemant @michelealbano

[wing328]

:+1 let me know if you need help on that.

[wing328]

https://github.com/OpenAPITools/openapi-generator/blob/master/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PowerShellClientCodegen.java#L988 maybe useful as a reference in constructing the example code as it can deal with self-referencing models.

[wing328]

#8981 is a good start.

Next milestone/target is to add auto-generated code examples that users can copy-and-paste.