Rework comment indentation to support non-JSDoc styles

[pzuraq]

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Short summary of your issue

We'd like to support the following comment style:

/**
  A foo class

  ```js
  foo({
    bar: 'baz'
  })
  \```

  @anArbitraryTag
*/

This is much easier to use when typing code examples, but currently all leading space gets stripped due to this line here. A better strategy may be to check for the indentation level of the first non-star character and strip up to that level instead. I can implement this if you agree, just let me know.

[MattMcFarland]

This project is dead, consider contributing to esdoc2 instead! https://github.com/esdoc2/esdoc2