Issue #27076: Doc, comment and test function name spelling fixes

Most fixes to Doc/ and Lib/ directories by Ville Skyttä.
diff --git a/Lib/encodings/utf_32.py b/Lib/encodings/utf_32.py
index 6c8016f..067e1e2 100644
--- a/Lib/encodings/utf_32.py
+++ b/Lib/encodings/utf_32.py
@@ -68,7 +68,7 @@
         self.decoder = None
 
     def getstate(self):
-        # additonal state info from the base class must be None here,
+        # additional state info from the base class must be None here,
         # as it isn't passed along to the caller
         state = codecs.BufferedIncrementalDecoder.getstate(self)[0]
         # additional state info we pass to the caller: