Slack's mrkdwn parser can fail to recognize the closing * of a bold span
when it is immediately preceded by a non-word character (), ], }, ., :,
em-dash, ...), mis-rendering the span and in reported cases truncating
the rest of the message. Insert a zero-width space (U+200B) between the
last character and the closing * whenever the last character is not
alphanumeric or underscore.
Reapplied from #35144 by @gonzalofrancoceballos — the original patched
gateway/platforms/slack.py, which was migrated to
plugins/platforms/slack/adapter.py in the plugin migration.
Gonzalo Franco Ceballos
cc64f0289a