[docs] Misc improvements

Closes #4987, Closes #4906, Closes #4919, Closes #4977, Closes #4979

yt_dlp/extractor/common.py

@@ -1236,7 +1236,7 @@ class InfoExtractor:
             fatal, has_default = False, True
 
         json_string = self._search_regex(
-            rf'{start_pattern}\s*(?P<json>{{\s*{contains_pattern}\s*}})\s*{end_pattern}',
+            rf'(?:{start_pattern})\s*(?P<json>{{\s*(?:{contains_pattern})\s*}})\s*(?:{end_pattern})',
             string, name, group='json', fatal=fatal, default=None if has_default else NO_DEFAULT)
         if not json_string:
             return default

yt_dlp/extractor/cybrary.py

@@ -1,11 +1,10 @@
-from .common import InfoExtractor
-
+from .common import InfoExtractor
 from ..utils import (
     ExtractorError,
     smuggle_url,
     str_or_none,
     traverse_obj,
-    urlencode_postdata
+    urlencode_postdata,
 )
 
 

yt_dlp/extractor/generic.py

@@ -2623,8 +2623,8 @@ class GenericIE(InfoExtractor):
 
         url, smuggled_data = unsmuggle_url(url, {})
         force_videoid = None
-        is_intentional = smuggled_data and smuggled_data.get('to_generic')
-        if smuggled_data and 'force_videoid' in smuggled_data:
+        is_intentional = smuggled_data.get('to_generic')
+        if 'force_videoid' in smuggled_data:
             force_videoid = smuggled_data['force_videoid']
             video_id = force_videoid
         else:

yt_dlp/extractor/niconico.py

@@ -557,8 +557,7 @@ class NiconicoPlaylistBaseIE(InfoExtractor):
     }
 
     def _call_api(self, list_id, resource, query):
-        "Implement this in child class"
-        pass
+        raise NotImplementedError('Must be implemented in subclasses')
 
     @staticmethod
     def _parse_owner(item):