Spelling fixes to docs, docstrings, and comments (GH-6374)

(cherry picked from commit 61f82e0e337f971da57f8f513abfe693edf95aa5)

Co-authored-by: Ville Skyttä <ville.skytta@iki.fi>
diff --git a/Doc/library/email.generator.rst b/Doc/library/email.generator.rst
index cc8e822..2575a51 100644
--- a/Doc/library/email.generator.rst
+++ b/Doc/library/email.generator.rst
@@ -185,7 +185,7 @@
       Convert any bytes with the high bit set as needed using an
       ASCII-compatible :mailheader:`Content-Transfer-Encoding`.  That is,
       transform parts with non-ASCII :mailheader:`Cotnent-Transfer-Encoding`
-      (:mailheader:`Content-Transfer-Encoding: 8bit`) to an ASCII compatibile
+      (:mailheader:`Content-Transfer-Encoding: 8bit`) to an ASCII compatible
       :mailheader:`Content-Transfer-Encoding`, and encode RFC-invalid non-ASCII
       bytes in headers using the MIME ``unknown-8bit`` character set, thus
       rendering them RFC-compliant.