Adding additional metadata to operations

By default, the first doc comment (if any) is taken for the summary field and the rest of the following doc comments (if any) will be taken as description for that operation.

/// Default
/// multiline
/// summary
///
/// Default
/// multiline
/// description
async fn my_handler() -> Json<Foo> { /* */ }

This can be overridden by explicitly specifying summary and description in the proc-macro attribute like so:

#[api_v2_operation(
  summary = "My awesome handler",
  description = "It creates a pretty JSON object",
  /// A few other parameters are also supported
  operation_id = "my_handler",
  consumes = "application/yaml, application/json",
  produces = "application/yaml, application/json",
  tags(Cats, Dogs, "Api reference"),
)]
async fn my_handler() -> Json<Foo> { /* */ }