symbols to the left OR symbols to the right of legend text), and
alignment for group/subgroup/item text
Allows creation of right-to-left locale friendly legends. Additionally,
we default to this right-to-left style alignment when creating new
legends under a RTL based locale.
This feature allows for expressions to be embedded directly inside
legend item text (e.g. group, subgroup and item text). The expressions
are evaluated at render time, with full knowledge of the legend's
expression context (so can utilise variables from the layout/layout item/
etc)
There's no UI for this yet (that will come in 3.8), but expressions are
entered using the standard [% 1 + 2 %] format.
E.g. a legend item text of
My layer (rendered at 1:[% @map_scale %])
will show in the output as
My layer (renderer at 1:1000)
