[docs,cleanup] Improve docs and minor cleanup

Closes #1387, #1404, #1408, #1485, #1415, #1450, #1492

yt_dlp/extractor/telemundo.py

@@ -1,4 +1,4 @@
-# coding=utf-8
+# coding: utf-8
 from __future__ import unicode_literals
 
 from .common import InfoExtractor