This feature is referred to as "code/data literals" in ASMotor,
and simply as "literals" in some older assemblers like MIDAS
for the PDP-10. RGBASM already had the "section fragments"
feature for keeping disparate contents together when linked,
so these worked naturally as "fragment literals".
This was removed in b3c0db218d
(along with two unrelated changes).
Removing this hack introduced issue #742, whereby INCLUDing
a file without a trailing newline can cause a syntax error.
A more proper fix would involve Bison's tracking locations,
but for now the EOF-newline hack fixes the issue while only
affecting some reported errors (expecting "newline"
instead of "end of file").
Fixes#742
