Add `<meter>` to `inlineTags`

According to [spec](https://html.spec.whatwg.org/multipage/form-elements.html#the-meter-element), `` is an inline element, and surrounding whitespace should be kept.

### Example:
``` html
This is
something
to be tested
```

### Expected:
``` html
This is something to be tested
```

### Result:
``` html
This issomethingto be tested
```

👆 Note the spaces before `` and after ``.

Start by locating the inlineTags definition and the existing handling or coverage for inline elements. Add meter to the relevant inline-element list, then verify that the example preserves whitespace before and after the meter element.

Written by the indexing model from the issue text.