bpo-34681: Rename class Pattern in sre_parse to State. (GH-9310)

Also rename corresponding attributes, parameters and variables.
diff --git a/Lib/re.py b/Lib/re.py
index 94d4865..68d62dc 100644
--- a/Lib/re.py
+++ b/Lib/re.py
@@ -334,7 +334,7 @@
         self.lexicon = lexicon
         # combine phrases into a compound pattern
         p = []
-        s = sre_parse.Pattern()
+        s = sre_parse.State()
         s.flags = flags
         for phrase, action in lexicon:
             gid = s.opengroup()