Clean up Vault docs in User Guide. (#46188)

* Fix spelling of 'separate' throughout.

* Various cleanups in the User Guide for Vault.

- Fix spelling of 'algorithm'
- Fix indentation of nested list in payload format
- Fix mysterious refernce to 'b_pkey1'.
- Fix reference to newline as '\n': the backslash is lost when rendered
to the docs website. Specify the hex value for newline instead of the
backslash escape.

* Fix formatting

* Update vault.rst

lib/ansible/module_utils/facts/system/distribution.py

@@ -88,7 +88,7 @@ class DistributionFiles:
     }
 
     # We can't include this in SEARCH_STRING because a name match on its keys
-    # causes a fallback to using the first whitespace seperated item from the file content
+    # causes a fallback to using the first whitespace separated item from the file content
     # as the name. For os-release, that is in form 'NAME=Arch'
     OS_RELEASE_ALIAS = {
         'Archlinux': 'Arch Linux'