Support links in reddit galleries

In the wild: https://redd.it/10vnkmy
Tests:
- A sane, ordinary test: https://redd.it/10vwtow
- 3*4096 occurances of <&> in captions and URLs: https://redd.it/10vxerk
- 3*200 occurances of <&> in captions and l&r in URLs: https://redd.it/10vxn7n

redditbot.py

@@ -52,8 +52,8 @@ if isinstance(_send_to_chats, list):
         send_to_chats[i] = j
 bot_admins = config_data['config']['bot_admins']
 
-def title_or_shortlink(submission):
-    title = submission.title.strip(''.join((
+def superstrip(text):
+    return text.strip(''.join((
         # https://en.wikipedia.org/wiki/Unicode_control_characters#Category_%22Cc%22_control_codes_(C0_and_C1)
         '\u0000', # NULL (used in null-terminated strings)
         '\u0009', # HORIZONTAL TABULATION (HT) (inserted by the tab key)
@@ -109,6 +109,9 @@ def title_or_shortlink(submission):
         '\u2060', # word joiner
         '\uFEFF', # zero width non-breaking space
     )))
+
+def title_or_shortlink(submission):
+    title = superstrip(submission.title)
     return f'<a href="{submission.shortlink}">{html.escape(title)}</a>' if title else submission.shortlink
 
 logging.basicConfig(level=logging.INFO)
@@ -424,9 +427,21 @@ async def main():
                             await _download_file(filename, media_metadata_item['s'][media_type])
                             break
                         caption = f'{text}\n#{count}'
-                        real_caption = (gallery_data_item.get('caption') or '').strip()
-                        if real_caption:
+                        real_caption = superstrip(gallery_data_item.get('caption') or '')
+                        outbound_url = gallery_data_item.get('outbound_url')
+                        # tested longest characters with https://redd.it/10vxerk, got 510 chars max
+                        # probably not a worry unless if they really up both limits
+                        if real_caption and outbound_url:
+                            caption += f': <a href="{html.escape(outbound_url)}">{html.escape(real_caption)}</a>'
+                        elif real_caption:
                             caption += f': {html.escape(real_caption)}'
+                        elif outbound_url:
+                            # outbound url is unlimited (for some reason)
+                            # a nice arbitrary 150 characters should be ok
+                            if len(outbound_url) <= 150:
+                                caption += f': {html.escape(outbound_url)}'
+                            else:
+                                caption += f': <a href="{html.escape(outbound_url)}">{html.escape(outbound_url[:150])}…</a>'
                         captions.append(caption)
                         files.append(filename)
                         count += 1