Added getPluginHelp() method to return docstring for individual plugins.

plugins/Plugin/plugin.py

@@ -47,8 +47,9 @@ class Plugin(callbacks.Plugin):
         Returns a useful description of how to use <plugin>, if the plugin has
         one.
         """
-        if hasattr(cb, '__doc__') and cb.__doc__:
-            irc.reply(utils.str.normalizeWhitespace(cb.__doc__))
+        doc = cb.getPluginHelp()
+        if doc:
+            irc.reply(utils.str.normalizeWhitespace(doc))
         else:
             irc.reply('That plugin is loaded, but has no plugin help.')
     help = wrap(help, ['plugin'])

src/callbacks.py

@@ -1191,6 +1191,11 @@ class PluginMixin(BasePlugin, irclib.IrcCallback):
         else:
             group.set(value)
 
+    def getPluginHelp(self):
+        if hasattr(self, '__doc__'):
+            return self.__doc__
+        else:
+            return None
 
 class Plugin(PluginMixin, Commands):
     pass