DEV: Correct typos and spelling mistakes (#12812)

Over the years we accrued many spelling mistakes in the code base. 

This PR attempts to fix spelling mistakes and typos in all areas of the code that are extremely safe to change 

- comments
- test descriptions
- other low risk areas

lib/middleware/enforce_hostname.rb

@@ -10,7 +10,7 @@ module Middleware
       # enforces hostname to match the hostname of our connection
       # this middleware lives after rails multisite so at this point
       # Discourse.current_hostname MUST be canonical, enforce it so
-      # all Rails helpers are guarenteed to use it unconditionally and
+      # all Rails helpers are guaranteed to use it unconditionally and
       # never generate incorrect links
       env[Rack::Request::HTTP_X_FORWARDED_HOST] = nil