Change HTML syntax to better match Material Theme

[lmlorca]

It seems it also affects html tags in PHP, so this change should also improve the syntax of templating engines that share the same base html vim syntax groups.

[kaicataldo]

Mind adding a screenshot for posterity?

[lmlorca]

Sorry I posted the result in the issue I opened but not here.

Darker:

Before:

Now:

Ocean:

Before:

Now:

Lighter:

Before:

Now:

Palenight:

Before:

Now:

So basically it improves basic HTML support by making the tags and the attributes different. Also it follows closer the original theme as well.

[kaicataldo]

Oh no, I didn’t mean to close this pull request. So sorry about that. Do you mind reopening it?