Check Swift reserved names when generating function names

[ialimz]

This PR fixes a bug that causes the Generator not to consider Swift reserved names such as the do keyword.

For example, assume we have an RPC like below:

service JsonRpc {
    rpc Do(Request) returns (Response) {}
}

If we don't consider Swift's do keyword, we will be going to have a compile error.

With these changes, the generated code should be like below:

public protocol JsonRpc_JsonRpcClientProtocol: GRPCClient {
  var serviceName: String { get }
  var interceptors: JsonRpc_JsonRpcClientInterceptorFactoryProtocol? { get }

  func `do`(
    _ request: JsonRpc_Request,
    callOptions: CallOptions?
  ) -> UnaryCall<JsonRpc_Request, JsonRpc_Response>
}

The changes idea is the same as SwiftProtobuf library

[linux-foundation-easycla]

The committers are authorized under a signed CLA.

• ✅ Ali Moazenzadeh (5cf158e)

[glbrntt]

Thanks, this looks good although I've left a couple of nits.

[ialimz]

Thanks @glbrntt
I've committed your suggestions

[glbrntt]

@ialimz could you run ./scripts/format.sh to make the formatting checks happy?

[glbrntt]

The other failures here are #1215 -- we can ignore those for now.

[ialimz]

@glbrntt SwiftFormat changes have been applied

[glbrntt]

Thanks @ialimz!