Configuration option to parse out all unescaped unknown @<tag> blocks

Currently something like this:

  /**
   * foo summary
   * 
   * @custom foo
   */
  export interface B {}

Leads to parsing @custom foo as part of the summary text.

Could there be a mode to treat any line-starting unescaped @<valid_tag_name> as an unknown tag block? It would parse as simply:

1. the name of the unknown tag
2. the content of the tag (first line and following lines until end or next tag)

A use-case for this would be a doc tool listing the unknown tags with relative niceness, e.g.

##### Unknown Tag 1

<content>

##### Unknown Tag 2

<content>

The issue names no files, tests, or entry points. Start by locating the TypeScript doc-comment parser and its handling of unknown tags; done means the requested mode separates each unescaped line-starting tag into its name and following content.