Say what order a terminal index actually follows

The comment on elementTerminals() said the order of Element::terminals()
"also comes from the definition", which reads as file order and is
wrong. Element::parseTerminal() re-sorts the list on every insertion, top
to bottom then left to right on each terminal's local position, so index 0
is the topmost terminal whatever order the .elmt lists them in.

bobine_ka_a_remanence.elmt writes A2 (y=20) before A1 (y=-20) and index 0
is A1. Measured by placing 400 shipped elements and reading the real order
back: a top-to-bottom, left-to-right prediction matched all 400, while
file order matched only the 100 where the two happen to coincide. Of the
837 shipped elements with distinct named terminals, 619 list them in a
different order than QElectroTech indexes them.

Comment only. Two terminals at one point tie and the sort is not stable;
the comment says so.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

sources/scripting/qetscriptapi.h

@@ -94,7 +94,9 @@ class DiagramImageItem;
 
 	  Terminals are addressed by their @b index in Element::terminals(),
 	  not by uuid, and elementTerminals() prints that indexing so a script
-	  can see what it is about to wire. Terminal uuids look like the
+	  can see what it is about to wire. The index is the terminal's place
+	  in the element's own top-to-bottom, left-to-right ordering, not the
+	  order its definition file lists them. Terminal uuids look like the
 	  obvious key and are not one: Terminal::uuid() is a property of the
 	  catalog .elmt definition, empty for most of the installed base and,
 	  where present, identical across every instance of that element -- so