Make operator case insensitive in tax queries

[clifgriffin]

In WP_Tax_Query::get_sql() the operator is assumed / required to be uppercase.

This conforms to preferred SQL syntax, but there isn't a good reason I can think of to enforce this here.

The simplest fix is is to force $operator to uppercase, allowing for a variety of input. I'm attaching a patch to that effect.

[wonderboymusic]

Needs whitespace rehabilitation

[clifgriffin]

Replying to wonderboymusic:

Not sure what you're referring to. Could you clarify? Happy to make any necessary changes.

Thanks!

[wonderboymusic]

I have attached a screenshot - needs to be tabs instead of spaces, and needs whitespace like so:

$operator = strtoupper( $operator );

[wonderboymusic]

In 28618:

When queries are passed to WP_Tax_Query, the value for operator is assumed to be uppercase. This is an unnecessary constraint. In ->get_sql(), cast it using $operator = strtoupper( $query['operator'] ).

Props clifgriffin.
Fixes #27557.