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

Most fixes to Doc/ and Lib/ directories by Ville Skyttä.
diff --git a/Demo/tkinter/matt/canvas-with-scrollbars.py b/Demo/tkinter/matt/canvas-with-scrollbars.py
index 81ef25a..8f81cad 100644
--- a/Demo/tkinter/matt/canvas-with-scrollbars.py
+++ b/Demo/tkinter/matt/canvas-with-scrollbars.py
@@ -1,7 +1,7 @@
 from Tkinter import *
 
-# This example program creates a scroling canvas, and demonstrates
-# how to tie scrollbars and canvses together. The mechanism
+# This example program creates a scrolling canvas, and demonstrates
+# how to tie scrollbars and canvases together. The mechanism
 # is analogus for listboxes and other widgets with
 # "xscroll" and "yscroll" configuration options.