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

Most fixes to Doc/ and Lib/ directories by Ville Skyttä.
diff --git a/Modules/sha256module.c b/Modules/sha256module.c
index 2ce8d92..8f18faa 100644
--- a/Modules/sha256module.c
+++ b/Modules/sha256module.c
@@ -101,7 +101,7 @@
  * 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://libtomcrypt.org
  */