Emphasis around link ignored when followed by a special punctuation character

[redstoneleo]

s1=r'''**[Usage](http://127.0.0.1:8000/cms/pages/82/edit/)**：'''
import mistletoe
from mistletoe import Document, HTMLRenderer
rendered = mistletoe.markdown(s1, HTMLRenderer)
print(rendered)

output:
<p>**<a href="http://127.0.0.1:8000/cms/pages/82/edit/">Usage</a>**：</p>
the correct should be :
<p><strong><a href="http://127.0.0.1:8000/cms/pages/82/edit/">Usage</a></strong>：</p>

[pbodnar]

@redstoneleo, thanks for the report. Luckily, this issue is already fixed in the master - by 0c05dcd within #96.

Details: This problem occurred only when using the special char of ： instead of the more common : (2 chars).