Don't document the removal of <mbedtls> as the module was removed.

Author: sadiepowell

docs/4/breaking-changes.md

@@ -86,8 +86,6 @@ title: v4 Breaking Changes
 
 - `<link:ssl>` has been moved to `<link:sslprofile>`. This move originally happened in v3 so if you are using a v3 config you probably don't need to do anything.
 
-- `<mbedtls>` has been removed (other than `<mbedtls:onrehash>`). You should configure a TLS (SSL) profile instead.
-
 - `<noctcp:enableumode>` has been removed with no replacement (now always enabled).
 
 - `<openssl>` has been removed (other than `<openssl:onrehash>`). You should configure a TLS (SSL) profile instead.