Fix typos in the Lib directory (GH-28775)

Fix typos in the Lib directory as identified by codespell.

Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>

Lib/difflib.py

@@ -62,7 +62,7 @@ class SequenceMatcher:
     notion, pairing up elements that appear uniquely in each sequence.
     That, and the method here, appear to yield more intuitive difference
     reports than does diff.  This method appears to be the least vulnerable
-    to synching up on blocks of "junk lines", though (like blank lines in
+    to syncing up on blocks of "junk lines", though (like blank lines in
     ordinary text files, or maybe "<P>" lines in HTML files).  That may be
     because this is the only method of the 3 that has a *concept* of
     "junk" <wink>.