Improve readability of attribute documentation

[ArthurClemens]

For some attributes, the displayed documentation is almost unreadable.

Rendered in phx_live_storybook:

The same documentation generated by ExDoc:

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Some suggestions:

• Documentation column
  • Render Markdown
  • Remove max-width: 16rem - this is far too small
  • Remove style white-space: pre-line;
• Column Default
  • Add style white-space: break-spaces;
  • Not styling per se, but the Value field cannot be edited when the value is a map

[cblavier]

I could indeed improve CSS, but I think that whatever I do, this won't render well in a table.
What do you think of truncating the doc to the first paragraph, and then click on it to expand full doc in a modal window?

There are also some redundant information: ExDoc generate documentation for default values, but this information is already visible in the next column

[ArthurClemens]

An expand option could work. Perhaps reveal it in an extra row below the current one.

[ArthurClemens]

I was thinking along these lines:

I've tweaked the data a bit:

• Trimmed the default value
• Rendered the code fragment inside a pre