[prop-loader] Better handling of generic types

[thompsongl]

Work done in #4125 to eliminate manual props info tables for complex components highlights room for improvement in documenting generic types:

EuiBasicTable makes use of cascading generics to typeitems, but this is not immediately clear in the docs, nor is it clear what shape T can take.

Updates should include some clearer indication that a type is generic, and some documentation about the default value, extension, or shape of the generic. It could be that we are limited by react-docgen-typescript.

[github-actions]

👋 Hey there. This issue hasn't had any activity for 180 days. We'll automatically close it if that trend continues for another week. If you feel this issue is still valid and needs attention please let us know with a comment.

[daveyholler]

@daveyholler - Look into how Storybook handles types in a props table

[github-actions]

👋 Hi there - this issue hasn't had any activity in 6 months. If the EUI team has not explicitly expressed that this is something on our roadmap, it's unlikely that we'll pick this issue up. We would sincerely appreciate a PR/community contribution if this is something that matters to you! If not, and there is no further activity on this issue for another 6 months (i.e. it's stale for over a year), the issue will be auto-closed.

[github-actions]

❌ Per our previous message, this issue is auto-closing after having been open and inactive for a year. If you strongly feel this is still a high-priority issue, or are interested in contributing, please leave a comment or open a new issue linking to this one for context.