Add various missing generic arguments (#7702)

Co-authored-by: Akuli <akuviljanen17@gmail.com>

stubs/Markdown/markdown/inlinepatterns.pyi

@@ -1,5 +1,5 @@
 import typing
-from typing import Any, Match
+from typing import Any, ClassVar, Match
 from xml.etree.ElementTree import Element
 
 def build_inlinepatterns(md, **kwargs): ...
@@ -94,7 +94,7 @@ class LinkInlineProcessor(InlineProcessor):
 class ImageInlineProcessor(LinkInlineProcessor): ...
 
 class ReferenceInlineProcessor(LinkInlineProcessor):
-    NEWLINE_CLEANUP_RE: typing.Pattern
+    NEWLINE_CLEANUP_RE: ClassVar[typing.Pattern[str]]
     def evalId(self, data, index, text): ...
     def makeTag(self, href, title, text): ...