Notice the end of jadeTagBlockText

This fixes a regression from my last PR, for the situation in which a tag-block is followed immediately (i.e. no intervening blank line) with another tag:

```jade
  p.
    Here is a paragraph.
  p
```

With the most recent pull the second tag is not recognized. This commit fixes that by treating the last line of a tag-block differently than the preceding lines.

`jadeTagBlockText` can continue for any number of lines, but after the last line of similar indentation we should be looking for tags, etc. again. The new syntax region `jadeTagBlockEnd` does this.