Opening saved snippets is exceptionally slow

[tom-writes-code]

When taking the option to load snippets, REPLLOAD is very slow to open. It is also slow to change user, or toggle between saved/unsaved snippets.

The call stack shows that it is spending a long time sat here:

The stated line is the "SELECT(...LISTAGG..." statement in fetchStoredSnippets()... which is almost certainly badly inefficient.