allow to open multiple buffers of the same type

We actively prevent opening multiple taglist or bufferlist buffers, but
so far allow to open multiple named query buffers. They cannot differ,
though, since there is nothing to configure about them.

Rather than confusing the user by behaving differently for different
buffer types, lift the restriction for all of them: at worst there are
multiple instances of buffers with the same content.

We do make a single exception for the bufferlist buffer because that is
the one you typically use to switch to other buffers.

alot/commands/globals.py

@@ -566,14 +566,7 @@ def __init__(self, filtfun=lambda x: x, tags=None, **kwargs):
 
     def apply(self, ui):
         tags = self.tags or ui.dbman.get_all_tags()
-        blists = ui.get_buffers_of_type(buffers.TagListBuffer)
-        if blists:
-            buf = blists[0]
-            buf.tags = tags
-            buf.rebuild()
-            ui.buffer_focus(buf)
-        else:
-            ui.buffer_open(buffers.TagListBuffer(ui, tags, self.filtfun))
+        ui.buffer_open(buffers.TagListBuffer(ui, tags, self.filtfun))
 
 
 @registerCommand(MODE, 'namedqueries')