Scope resolution fails from link under scope to directory based scope

[cirosantilli]

At 0466217

notindex.bigb

= Notindex
{scope}

<notindex 2>

notindex/notindex-2.bigb

= Notindex 2

Convert:

ourbigbook .

Conversion fails with:

notindex.bigb:4:2: cross reference to unknown id: "notindex-2" at render time

but:

sqlite3 out/db.sqlite3 'select idid from Id'

shows that notindex/notindex-2 is there.

#229 feels related/same base cause.

The following analogous constructs work however:

1. single source scope

= Notindex
{scope}

<notindex 2>

== Notindex 2

2. everything in directory based scope: move notindex.bigb to notindex/index.bigb

notindex/index.bigb

= Notindex

<notindex 2>

and

notindex/notindex-2.bigb

= Notindex 2