Remove `meta` from list of block tags...

...in start condition #6 of HTML blocks.  meta tags are used
in some inline contexts (though this isn't valid HTML5), e.g.
in schema.org.  Example:

```
This paragraph is closed right after an opening span:
<span itemprop="contentLocation" itemscope itemtype="https://schema.org/City">
  <meta itemprop="name" content="Springfield">
  <span itemprop="address" itemscope itemtype="https://schema.org/PostalAddress">
    <meta itemprop="addressCountry" content="US">
    <span itemprop="addressLocality">Springfield</span>,
    <span itemprop="addressRegion">Oregon</span>
    <meta itemprop="postalCode" content="97477">
  </span>
</span>
```

Closes #527.

0 files changed, 0 insertions, 0 deletions