Unfortunately I found no way to use the ↳ glyph in Texinfo, so I used
@arrow{} instead, which has a different width, so we have to have all
the examples doubled, once for TeX, another for the rest of the world.
* doc/bison.texi: Use the current display in the examples.
* doc/calc.y, doc/ids.y, doc/if-then-else.y, doc/sequence.y: New.
