Doc/Michelson: redirect events to interactive reference

Context

Answers this part of #4077:

• delete the parts about instructions from the static reference:
  • Events

The documentation about the EMIT instruction is added to the interactive reference: michelson-reference!115 (merged).

Also closes #3847 (closed).

Manually testing the MR

make -C docs -j

And then open docs/_build/alpha/michelson.html in a web browser.

Or open the exposed artifacts Documentation - excluding old protocols below, and navigate to docs/_build/alpha/michelson.html.

Checklist

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