Fix parsing error with <br> tags in markdown files

[osteele]

Description

Gojekyll currently terminates with an 'EOF' error when encountering <br> tags in markdown files, while Jekyll's Kramdown processor handles them correctly.

Background

This issue was originally reported as part of #51, where it was discovered that the presence of <br> tags in markdown files causes parsing errors.

Steps to reproduce

Create a markdown file with the following content:

<div markdown=\"1\">
<br>
<br>
</div>

Actual behavior

Gojekyll terminates with an error message: filename.md: markdown: EOF

Expected behavior

Gojekyll should properly parse and render the HTML tags, similar to how Jekyll's Kramdown processor handles them.

Workaround

As noted in issue #51, using self-closing tags (<br/>) instead of <br> appears to work as a workaround.