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

Most fixes to Doc/ and Lib/ directories by Ville Skyttä.
diff --git a/Lib/collections.py b/Lib/collections.py
index 7ecfd46..f2ad972 100644
--- a/Lib/collections.py
+++ b/Lib/collections.py
@@ -314,7 +314,7 @@
     >>> x, y = p                        # unpack like a regular tuple
     >>> x, y
     (11, 22)
-    >>> p.x + p.y                       # fields also accessable by name
+    >>> p.x + p.y                       # fields also accessible by name
     33
     >>> d = p._asdict()                 # convert to a dictionary
     >>> d['x']