Close fenced div on CRLF input (fixes #113)

[youdie006]

Fixes #113.

Problem

With CRLF line endings, a fenced div's closing ::: fence is not detected, so the div never closes and all following content is swallowed inside it.

renderHTML(parse(":::\r\nhello\r\n:::\r\nafter\r\n"))

Buggy CRLF output ("after" trapped inside an unclosed div):

<div>
<p>hello

after</p>
</div>

Correct output (the LF equivalent already produces this):

<div>
<p>hello</p>
</div>
<p>after</p>

Root cause

In the fenced_div continue callback (src/block.ts), when the closing fence matches, the parser sets this.pos = m.endpos. The fence pattern (::::*)[ \t]*\r?\n matches through the \n, so on CRLF input m.endpos lands on the \n -- one position past the \r that getEol() records as starteol. The main loop then evaluates the blank-line check isBlank = (pos === starteol) as false, so the fence line is mistaken for a lazy paragraph continuation and the div is never closed. On LF input m.endpos and starteol coincide, so the check passes and it works by coincidence.

Fix

Set this.pos = this.starteol, the position just before the line ending, which is correct for both LF and CRLF. This mirrors the sibling code_block close path and djot.js's \r?\n CRLF handling throughout the lexer. LF output is byte-identical; CRLF now closes the div correctly.

Tests

Added a regression test in src/html.spec.ts asserting the CRLF input closes the div (byte-identical to the LF output, which is also asserted unchanged). All existing tests pass (tsc + jest, 417 total).

Thanks to @iorizu for the clear report.

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This change was prepared with AI assistance and reviewed by me before submission.