Issue #27076: Doc, comment and tests spelling fixes

Most fixes to Doc/ and Lib/ directories by Ville Skyttä.
diff --git a/Modules/sha512module.c b/Modules/sha512module.c
index 8237d86..76942aa 100644
--- a/Modules/sha512module.c
+++ b/Modules/sha512module.c
@@ -111,7 +111,7 @@
  * algorithms in a highly modular and flexible manner.
  *
  * The library is free for all purposes without any express
- * gurantee it works.
+ * guarantee it works.
  *
  * Tom St Denis, tomstdenis@iahu.ca, http://libtom.org
  */