Move the a tag from the block to inline in HTMLParser | Fixes #371

[matuzalemsteles]

This fixes #371, with references.

• https://developer.mozilla.org/en-US/docs/Web/HTML/Inline_elements
• https://www.w3schools.com/html/html_blocks.asp

[brunobasto]

LGTM, but wondering if we can run any kind of tests with this change applied and see if anything in Metal breaks.

[yuchi]

Please pay attention that a is a special element that can contain both block and inline elements.

I didn't look at the source but looks like you are inferring the child type of an element based on what kind of element it is, while the spec is a little bit more complex AFAIK.

[matuzalemsteles]

@brunobasto, I'm adding some cases to the tests that it broke before when it was in the Block elements list and adding some cases of using it as block and inline.

hey @yuchi, thanks for your concerns, as the current parser it follows this line of inferring the elements in block and inline ... I am just adding one more exception to a element since we can do it from block or inline. Thanks!