reddit, test: even more of the comments link format is optional

Reddit will accept /r/subreddit/comments/id, /comments/id, or even just
/id... The variations never end.

sopel/modules/reddit.py

@@ -29,7 +29,7 @@
 subreddit_url = r'%s/r/([\w-]+)/?$' % domain
 post_or_comment_url = (
     domain +
-    r'/r/\S+?/comments/(?P<submission>[\w-]+)'
+    r'(?:/r/\S+?)?/comments/(?P<submission>[\w-]+)'
     r'(?:/?(?:[\w%]+/(?P<comment>[\w-]+))?)'
 )
 short_post_url = r'https?://(redd\.it|reddit\.com)/(?P<submission>[\w-]+)/?$'

test/modules/test_modules_reddit.py

@@ -33,8 +33,14 @@ def bot(botfactory, configfactory):
     'https://reddit.com/r/subname/',
     'https://www.reddit.com/r/subname',
     'https://www.reddit.com/r/subname/',
+    'https://reddit.com/comments/123456',
+    'https://reddit.com/comments/123456/',
+    'https://www.reddit.com/comments/123456',
+    'https://www.reddit.com/comments/123456/',
     'https://reddit.com/r/subname/comments/123456',
     'https://reddit.com/r/subname/comments/123456/',
+    'https://www.reddit.com/comments/123456?param=value',
+    'https://www.reddit.com/comments/123456/?param=value',
     'https://reddit.com/r/subname/comments/123456?param=value',
     'https://reddit.com/r/subname/comments/123456/?param=value',
     'https://www.reddit.com/r/subname/comments/123456',
@@ -54,9 +60,6 @@ def bot(botfactory, configfactory):
     'https://reddit.com/r/subname/?param=value',
     'https://www.reddit.com/r/subname?param=value',
     'https://www.reddit.com/r/subname/?param=value',
-    # "shortlink" style allegedly seen in the wild, but not currently recognized
-    'https://reddit.com/comments/123456',
-    'https://reddit.com/comments/123456/',
 )