Add support for more tags

[WilliamRagstad]

There are only a small selection of tags supported in the current version of docthis. TSDoc wants to formalize a standard so that different tools can extract content without getting confused by each other’s markup.
This is important to keep support for all documentation generators used by different developers, and hence we should add the missing tags proposed by TSDoc.

Such tags are eg:

• @remarks
• @Alpha
• @beta

Here is a populated list of all tags we should add with alpha as the first tag: https://tsdoc.org/pages/tags/alpha/
And take a look at the different tag kinds: https://tsdoc.org/pages/spec/tag_kinds/

[WilliamRagstad]

There should also be dedicated extension settings for auto-generated tags if they are to be included or not.