Preferred Alias Declaration Style

[Vijay Nayar]

Most of the documentation at 
https://dlang.org/spec/declaration.html#alias uses examples of 
the form:  `alias aliasName = other;`, where `aliasName` becomes 
the new name to reference `other`.  Alternatively, one may write 
`alias other aliasName;`.  My understanding is that the syntax 
with `=` is the preferred one stylistically.

However, when it comes to `alias this` declarations, the only 
syntax supported is `alias other this;`, and one cannot write 
`alias this = other;`.

Does this mean that the `alias other aliasName;` syntax is 
preferred, or does it simply mean that this is a low priority 
issue that hasn't been addressed yet?