Consolidate the JSON and YAML examples in the specs into one codeblock to reduce the readers scroll effort

[nikhilkalburgi]

Description:

Currently, the examples in the specs are shown in two variants (JSON and YAML) and displayed vertically one below the other. This increases the scrolling effort of the readers.

Reproduce by navigating to https://www.asyncapi.com/docs/reference/specification/v3.0.0#specification

Proposal:

To reduce this effort, I propose to combine the examples in a single block each and let the readers decide to choose between JSON or YAML by building tabs right above the example code block.

Screenshots: Change highlighted in red

[github-actions]

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