Proposal - Improve attribute parsing

[jmooring]

Users are accustomed to quoting HTML attributes, regardless of type, because many have no concept of type. And the browser doesn't care. I understand this is markdown, not HTML, but there is a similar expectation from non-developer users.

With this module, quoting or not quoting an attribute makes a big difference.

Example	Notes
{linenostart="1"}	Panic (see #27)
{linenos="false"}	Effectively setting it to true
{hl_lines="[2]"}	Ignored

[yuin]

This is not only for this extension, but for the goldmark core.

Could you create a new discussion in yuin/goldmark?