Extra paragraphs incorrectly spawning when ":end:" appears.

["Tom Alexander" <tom@fizz.buzz>]

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This test document has 1 paragraph:
```
foo
bar
baz
```
which parses as:
```
(section
  (paragraph "foo\nbar\nbaz\n")
)
```

This test document should have 1 paragraph but org-mode is parsing it as 2:
```
foo
:end:
baz
```

which parses as:
```
(section
  (paragraph "foo\n")
  (paragraph ":end:\nbaz\n")
)
```

The paragraph documentation[1] states that:
> Empty lines and other elements end paragraphs.

But the document contains no empty lines and we can see in the output that it only contains paragraphs.

[1] https://orgmode.org/worg/org-syntax.html#Paragraphs

--
Tom Alexander
pgp: https://fizz.buzz/pgp.asc

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