Org reader: TODO and DONE labels require extra spaces

[atbest]

When the headlines contain task status labels like TODO or DONE, the labels affect parsing of following inline elements if only one space exists. For example, in the following codes, the first line has only one space after DONE and the second line has two spaces after DONE. Emacs can parse /italic/ correctly for both lines, however, Pandoc cannot recognize /italic/ in the first line and it only parses the second line correctly.

Org code:

** DONE /italic/ one space
** DONE  /italic/ two spaces

Emacs output:

<div id="outline-container-org80d58ab" class="outline-2">
<h2 id="org80d58ab"><span class="section-number-2">1</span> <span class="done DONE">DONE</span> <i>italic</i> one space</h2>
</div>
<div id="outline-container-org99010cd" class="outline-2">
<h2 id="org99010cd"><span class="section-number-2">2</span> <span class="done DONE">DONE</span> <i>italic</i> two spaces</h2>
</div>

Pandoc output:

<h2 id="italic-one-space"><span class="done DONE">DONE</span> /italic/ one space</h2>
<h2 id="italic-two-spaces"><span class="done DONE">DONE</span> <em>italic</em> two spaces</h2>