Create a word usage consistency test

There are some combinations of words where neither one is wrong,
like 'real time' vs 'real-time', but the TW team needs to pick one
and stick with it. This test provides suggestion-level Vale results
to encourage consistent usage.

doc/.vale/gitlab/SubstitutionWarning.yml

@@ -13,8 +13,11 @@ ignorecase: true
 swap:
   admin: administrator
   blacklist(ed|ing)?: denylist
+  code base: codebase
   config: configuration
   distro: distribution
+  file name: filename
+  filesystem: file system
   info: information
   repo: repository
   whitelist(ed|ing)?: allowlist