Loosen up emoji regex. (i.e. More emojis! 👍)

Now parsed: 🍺,🍺;🍺!

 If \w characters surround :foo:, we still say it's NOT an
 emoji, but we used to do this for \S characters, so it's loosened up.

(imported from commit 49b33d2f0ffdcfde8947ae411a4addcf4c24af9c)

zerver/lib/bugdown/__init__.py

@@ -580,7 +580,7 @@ class Bugdown(markdown.Extension):
 
         md.inlinePatterns.add('gravatar', Gravatar(r'!gravatar\((?P<email>[^)]*)\)'), '_begin')
         md.inlinePatterns.add('usermention', UserMentionPattern(mention.find_mentions), '>backtick')
-        md.inlinePatterns.add('emoji', Emoji(r'(?<!\S)(?P<syntax>:[^:\s]+:)(?!\S)'), '_begin')
+        md.inlinePatterns.add('emoji', Emoji(r'(?<!\w)(?P<syntax>:[^:\s]+:)(?!\w)'), '_begin')
         md.inlinePatterns.add('link', AtomicLinkPattern(markdown.inlinepatterns.LINK_RE, md), '>backtick')
 
         for (pattern, format_string) in self.getConfig("realm_filters"):

zerver/tests.py

@@ -2510,6 +2510,16 @@ xxxxxxx</strong></p>\n<p>xxxxxxx xxxxx xxxx xxxxx:<br>\n<code>xxxxxx</code>: xxx
         self.assertEqual(converted, '<p>test ' + emoji_img(':smile:') + ' again ' + emoji_img(':poop:') + '<br>\n'
                                   + ':) foo:)bar x::y::z :wasted waste: :fakeemojithisshouldnotrender:</p>')
 
+        msg = ':smile:, :smile:; :smile:'
+        converted = bugdown_convert(msg)
+        self.assertEqual(converted,
+            '<p>' +
+            emoji_img(':smile:') +
+            ', ' +
+            emoji_img(':smile:') +
+            '; ' +
+            emoji_img(':smile:') +
+            '</p>')
 
     def test_multiline_strong(self):
         msg = "Welcome to **the jungle**"