Full text search - wildcard and a stop word

I'm venturing into full text search in Postgres for the first time, and I'd like to be able to do a search by the start of a word - so I used the `:*` operator. However, this doesn't operate as I'd expect with a stop word - for example, my name is "Allan" so I often use it as a test string. It contains `all` which is a stop word, which is how I noticed this issue.

To illustrate:

=> select to_tsquery('al:*');
 to_tsquery
------------
 'al':*
(1 row)

=> select to_tsquery('all:*');
NOTICE:  text-search query contains only stop words or doesn't contain lexemes, ignored
 to_tsquery
------------
(1 row)

=> select to_tsquery('alla:*');
 to_tsquery
------------
 'alla':*
(1 row)

I get why that is happening - the notification basically details it, but the wildcard at the end seems to me that it should return `'all':*` in this case? Is this by design or could it be considered a bug? I'm using Postgres 12.10.

Thanks,
Allan