correct invalid void tags

app/lib/babycode.py

@@ -6,7 +6,7 @@ from pygments.lexers import get_lexer_by_name
 from pygments.util import ClassNotFound as PygmentsClassNotFound
 import re
 
-BABYCODE_VERSION = 7
+BABYCODE_VERSION = 8
 
 class BabycodeError(Exception):
     pass
@@ -441,15 +441,15 @@ RSS_TAGS = {
 VOID_TAGS = {
     'lb': lambda attr: '[',
     'rb': lambda attr: ']',
-    '@': lambda attr: '@',
-    '-': lambda attr: '-',
+    'at': lambda attr: '@',
+    'd': lambda attr: '-',
 }
 
 # [img] is considered block for the purposes of collapsing whitespace,
 # despite being potentially inline (since the resulting <img> tag is inline, but creates a block container around itself and sibling images).
 # [code] has a special case in is_inline().
 INLINE_TAGS = {
-    'b', 'i', 's', 'u', 'color', 'big', 'small', 'url', 'lb', 'rb', '@'
+    'b', 'i', 's', 'u', 'color', 'big', 'small', 'url', 'lb', 'rb', 'at', 'd'
 }
 
 def is_tag(e, tag=None):